77915231689 has 9 divisors (see below), whose sum is σ = 79621680877. Its totient is φ = 76244620684.

The previous prime is 77915231663. The next prime is 77915231717. The reversal of 77915231689 is 98613251977.

The square root of 77915231689 is 279133.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 77915231689 - 2²⁵ = 77881677257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77915231389) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13116282 + ... + 13122220.

Almost surely, 2^77915231689 is an apocalyptic number.

77915231689 is the 279133-rd square number.

77915231689 is the 139567-th centered octagonal number.

It is an amenable number.

77915231689 is a deficient number, since it is larger than the sum of its proper divisors (1706449188).

77915231689 is an frugal number, since it uses more digits than its factorization.

77915231689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11972 (or 5986 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 58.

The spelling of 77915231689 in words is "seventy-seven billion, nine hundred fifteen million, two hundred thirty-one thousand, six hundred eighty-nine".