77864844931 has 2 divisors, whose sum is σ = 77864844932. Its totient is φ = 77864844930.

The previous prime is 77864844929. The next prime is 77864844973. The reversal of 77864844931 is 13944846877.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77864844931 - 2¹ = 77864844929 is a prime.

It is a super-2 number, since 2×77864844931² (a number of 23 digits) contains 22 as substring.

Together with 77864844929, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 77864844931.

It is not a weakly prime, because it can be changed into another prime (77864844331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38932422465 + 38932422466.

It is an arithmetic number, because the mean of its divisors is an integer number (38932422466).

Almost surely, 2^77864844931 is an apocalyptic number.

77864844931 is a deficient number, since it is larger than the sum of its proper divisors (1).

77864844931 is an equidigital number, since it uses as much as digits as its factorization.

77864844931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32514048, while the sum is 61.

The spelling of 77864844931 in words is "seventy-seven billion, eight hundred sixty-four million, eight hundred forty-four thousand, nine hundred thirty-one".