77931 has 12 divisors (see below), whose sum is σ = 128752. Its totient is φ = 44496.

The previous prime is 77929. The next prime is 77933. The reversal of 77931 is 13977.

77931 = 68² + 69² + ... + 81².

It is an interprime number because it is at equal distance from previous prime (77929) and next prime (77933).

It is not a de Polignac number, because 77931 - 2¹ = 77929 is a prime.

It is a super-2 number, since 2×77931² = 12146481522, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is a nialpdrome in base 5.

It is a junction number, because it is equal to n+sod(n) for n = 77895 and 77904.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 77931.

It is not an unprimeable number, because it can be changed into a prime (77933) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 556 + ... + 681.

2⁷⁷⁹³¹ is an apocalyptic number.

77931 is a deficient number, since it is larger than the sum of its proper divisors (50821).

77931 is a wasteful number, since it uses less digits than its factorization.

77931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1250 (or 1247 counting only the distinct ones).

The product of its digits is 1323, while the sum is 27.

The square root of 77931 is about 279.1612437284. The cubic root of 77931 is about 42.7139842348.

The spelling of 77931 in words is "seventy-seven thousand, nine hundred thirty-one".