77310915561 has 16 divisors (see below), whose sum is σ = 124946934720. Its totient is φ = 46855100160.

The previous prime is 77310915557. The next prime is 77310915587. The reversal of 77310915561 is 16551901377.

77310915561 is a `hidden beast` number, since 7 + 7 + 3 + 1 + 0 + 91 + 556 + 1 = 666.

It is not a de Polignac number, because 77310915561 - 2² = 77310915557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77310915541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 130152760 + ... + 130153353.

It is an arithmetic number, because the mean of its divisors is an integer number (7809183420).

Almost surely, 2^77310915561 is an apocalyptic number.

It is an amenable number.

77310915561 is a deficient number, since it is larger than the sum of its proper divisors (47636019159).

77310915561 is a wasteful number, since it uses less digits than its factorization.

77310915561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260306133 (or 260306127 counting only the distinct ones).

The product of its (nonzero) digits is 198450, while the sum is 45.

The spelling of 77310915561 in words is "seventy-seven billion, three hundred ten million, nine hundred fifteen thousand, five hundred sixty-one".