77912719649 has 2 divisors, whose sum is σ = 77912719650. Its totient is φ = 77912719648.

The previous prime is 77912719631. The next prime is 77912719681. The reversal of 77912719649 is 94691721977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77426958049 + 485761600 = 278257^2 + 22040^2 .

It is a cyclic number.

It is not a de Polignac number, because 77912719649 - 2²⁴ = 77895942433 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 77912719591 and 77912719600.

It is not a weakly prime, because it can be changed into another prime (77912719609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38956359824 + 38956359825.

It is an arithmetic number, because the mean of its divisors is an integer number (38956359825).

Almost surely, 2^77912719649 is an apocalyptic number.

It is an amenable number.

77912719649 is a deficient number, since it is larger than the sum of its proper divisors (1).

77912719649 is an equidigital number, since it uses as much as digits as its factorization.

77912719649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12002256, while the sum is 62.

The spelling of 77912719649 in words is "seventy-seven billion, nine hundred twelve million, seven hundred nineteen thousand, six hundred forty-nine".