78972638 has 4 divisors (see below), whose sum is σ = 118458960. Its totient is φ = 39486318.

The previous prime is 78972631. The next prime is 78972697. The reversal of 78972638 is 83627987.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78972631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19743158 + ... + 19743161.

It is an arithmetic number, because the mean of its divisors is an integer number (29614740).

Almost surely, 2^78972638 is an apocalyptic number.

78972638 is a deficient number, since it is larger than the sum of its proper divisors (39486322).

78972638 is a wasteful number, since it uses less digits than its factorization.

78972638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39486321.

The product of its digits is 1016064, while the sum is 50.

The square root of 78972638 is about 8886.6550512552. The cubic root of 78972638 is about 429.0344985958.

The spelling of 78972638 in words is "seventy-eight million, nine hundred seventy-two thousand, six hundred thirty-eight".