78557978 has 16 divisors (see below), whose sum is σ = 120496896. Its totient is φ = 38397840.

The previous prime is 78557959. The next prime is 78557987. The reversal of 78557978 is 87975587.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31775 + ... + 34157.

It is an arithmetic number, because the mean of its divisors is an integer number (7531056).

Almost surely, 2^78557978 is an apocalyptic number.

78557978 is a deficient number, since it is larger than the sum of its proper divisors (41938918).

78557978 is a wasteful number, since it uses less digits than its factorization.

78557978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2749.

The product of its digits is 4939200, while the sum is 56.

The square root of 78557978 is about 8863.2938572519. The cubic root of 78557978 is about 428.2822729622.

The spelling of 78557978 in words is "seventy-eight million, five hundred fifty-seven thousand, nine hundred seventy-eight".