78906538 has 4 divisors (see below), whose sum is σ = 118359810. Its totient is φ = 39453268.

The previous prime is 78906521. The next prime is 78906557. The reversal of 78906538 is 83560987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83560987 = 431 ⋅193877.

It can be written as a sum of positive squares in only one way, i.e., 72641529 + 6265009 = 8523^2 + 2503^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19726633 + ... + 19726636.

Almost surely, 2^78906538 is an apocalyptic number.

78906538 is a deficient number, since it is larger than the sum of its proper divisors (39453272).

78906538 is a wasteful number, since it uses less digits than its factorization.

78906538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39453271.

The product of its (nonzero) digits is 362880, while the sum is 46.

The square root of 78906538 is about 8882.9352130926. The cubic root of 78906538 is about 428.9147647363.

The spelling of 78906538 in words is "seventy-eight million, nine hundred six thousand, five hundred thirty-eight".