77931317 has 4 divisors (see below), whose sum is σ = 77949036. Its totient is φ = 77913600.

The previous prime is 77931307. The next prime is 77931341. The reversal of 77931317 is 71313977.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 71313977 = 7 ⋅10187711.

It can be written as a sum of positive squares in 2 ways, for example, as 65918161 + 12013156 = 8119^2 + 3466^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77931317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77931307) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3317 + ... + 12917.

It is an arithmetic number, because the mean of its divisors is an integer number (19487259).

Almost surely, 2^77931317 is an apocalyptic number.

It is an amenable number.

77931317 is a deficient number, since it is larger than the sum of its proper divisors (17719).

77931317 is an equidigital number, since it uses as much as digits as its factorization.

77931317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17718.

The product of its digits is 27783, while the sum is 38.

The square root of 77931317 is about 8827.8716007880. The cubic root of 77931317 is about 427.1404215058.

The spelling of 77931317 in words is "seventy-seven million, nine hundred thirty-one thousand, three hundred seventeen".