813931 has 2 divisors, whose sum is σ = 813932. Its totient is φ = 813930.

The previous prime is 813907. The next prime is 813961. The reversal of 813931 is 139318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 813931 - 2⁹ = 813419 is a prime.

It is a super-2 number, since 2×813931² = 1324967345522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 813896 and 813905.

It is not a weakly prime, because it can be changed into another prime (813961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406965 + 406966.

It is an arithmetic number, because the mean of its divisors is an integer number (406966).

2⁸¹³⁹³¹ is an apocalyptic number.

813931 is a deficient number, since it is larger than the sum of its proper divisors (1).

813931 is an equidigital number, since it uses as much as digits as its factorization.

813931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 813931 is about 902.1812456486. The cubic root of 813931 is about 93.3675285699.

The spelling of 813931 in words is "eight hundred thirteen thousand, nine hundred thirty-one".