Calculators
Armstrong Number Calculator
Check Armstrong (narcissistic) numbers with an exact digit-power sum, privately in your browser.
An Armstrong (narcissistic) number equals the sum of its decimal digits each raised to the number of digits. Enter up to 1000 digits; leading zeros are removed. Calculations stay in your browser.
How to check an Armstrong number
An Armstrong number, also called a narcissistic number, is a nonnegative base-10 integer equal to the sum of its digits each raised to the number of digits. For 153, there are three digits and 1^3 + 5^3 + 3^3 = 153, so it qualifies. For 154, the sum is 190, so it does not. Other examples are 370, 371, 407 and 9474. Every single-digit nonnegative integer qualifies, including zero because 0^1 = 0. Enter up to 1000 decimal digits with no signs, separators, decimals or exponent notation. Surrounding whitespace is accepted. Leading zeros are removed before counting digits: 00153 is checked as 153 with exponent three. Each digit power and the total use exact integer arithmetic, so large inputs are never rounded. The calculation performs one digit-power sum rather than a repeated sequence. The result, digit count and full expression run locally in your browser.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What is an Armstrong number?
A nonnegative integer equal to the sum of its digits each raised to its digit count. For example, 153 = 1^3 + 5^3 + 3^3.
Is zero an Armstrong number?
Yes. Zero has one digit and 0^1 equals zero. Every single-digit nonnegative integer qualifies.
Do leading zeros change the exponent?
No. Leading zeros are removed before counting digits, so 00153 is checked as the three-digit number 153.
Are large integers rounded?
No. Exact integer arithmetic supports inputs of up to 1000 digits. Signs, separators, decimals and scientific notation are rejected.
Are my inputs uploaded?
No. All calculations run locally in your browser.