77915961 has 12 divisors (see below), whose sum is σ = 112949460. Its totient is φ = 51757440.

The previous prime is 77915951. The next prime is 77915963. The reversal of 77915961 is 16951977.

It can be written as a sum of positive squares in 2 ways, for example, as 59768361 + 18147600 = 7731^2 + 4260^2 .

It is not a de Polignac number, because 77915961 - 2⁷ = 77915833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77915963) 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, 12876 + ... + 17933.

It is an arithmetic number, because the mean of its divisors is an integer number (9412455).

Almost surely, 2^77915961 is an apocalyptic number.

It is an amenable number.

77915961 is a deficient number, since it is larger than the sum of its proper divisors (35033499).

77915961 is a wasteful number, since it uses less digits than its factorization.

77915961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31096 (or 31093 counting only the distinct ones).

The product of its digits is 119070, while the sum is 45.

The square root of 77915961 is about 8827.0018126202. The cubic root of 77915961 is about 427.1123643249.

The spelling of 77915961 in words is "seventy-seven million, nine hundred fifteen thousand, nine hundred sixty-one".