78131904 has 56 divisors (see below), whose sum is σ = 213408768. Its totient is φ = 25201920.

The previous prime is 78131891. The next prime is 78131909. The reversal of 78131904 is 40913187.

It is a super-2 number, since 2×78131904² = 12209188845330432, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (78131909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 612 + ... + 12515.

Almost surely, 2^78131904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78131904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106704384).

78131904 is an abundant number, since it is smaller than the sum of its proper divisors (135276864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78131904 is a wasteful number, since it uses less digits than its factorization.

78131904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13173 (or 13163 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 78131904 is about 8839.2253054213. The cubic root of 78131904 is about 427.5065790171.

The spelling of 78131904 in words is "seventy-eight million, one hundred thirty-one thousand, nine hundred four".