815931481 has 2 divisors, whose sum is σ = 815931482. Its totient is φ = 815931480.

The previous prime is 815931419. The next prime is 815931517. The reversal of 815931481 is 184139518.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 812763081 + 3168400 = 28509^2 + 1780^2 .

It is a cyclic number.

It is not a de Polignac number, because 815931481 - 2⁷ = 815931353 is a prime.

It is a super-2 number, since 2×815931481² = 1331488363373706722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (815931401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407965740 + 407965741.

It is an arithmetic number, because the mean of its divisors is an integer number (407965741).

Almost surely, 2^815931481 is an apocalyptic number.

It is an amenable number.

815931481 is a deficient number, since it is larger than the sum of its proper divisors (1).

815931481 is an equidigital number, since it uses as much as digits as its factorization.

815931481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 40.

The square root of 815931481 is about 28564.5143666053. The cubic root of 815931481 is about 934.4395894412.

The spelling of 815931481 in words is "eight hundred fifteen million, nine hundred thirty-one thousand, four hundred eighty-one".