78642865 has 32 divisors (see below), whose sum is σ = 113319936. Its totient is φ = 51226560.

The previous prime is 78642853. The next prime is 78642923. The reversal of 78642865 is 56824687.

It is a de Polignac number, because none of the positive numbers 2^k-78642865 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 169624 + ... + 170086.

It is an arithmetic number, because the mean of its divisors is an integer number (3541248).

Almost surely, 2^78642865 is an apocalyptic number.

It is an amenable number.

78642865 is a deficient number, since it is larger than the sum of its proper divisors (34677071).

78642865 is a wasteful number, since it uses less digits than its factorization.

78642865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709.

The product of its digits is 645120, while the sum is 46.

The square root of 78642865 is about 8868.0812468087. The cubic root of 78642865 is about 428.4364797074.

It can be divided in two parts, 78642 and 865, that added together give a cube (79507 = 43³).

The spelling of 78642865 in words is "seventy-eight million, six hundred forty-two thousand, eight hundred sixty-five".