78139904 has 20 divisors (see below), whose sum is σ = 156128214. Its totient is φ = 39069696.

The previous prime is 78139903. The next prime is 78139931. The reversal of 78139904 is 40993187.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 46240000 + 31899904 = 6800^2 + 5648^2 .

It is a super-2 number, since 2×78139904² = 12211689194258432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78139903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 75797 + ... + 76820.

Almost surely, 2^78139904 is an apocalyptic number.

It is an amenable number.

78139904 is a deficient number, since it is larger than the sum of its proper divisors (77988310).

78139904 is an equidigital number, since it uses as much as digits as its factorization.

78139904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152635 (or 152619 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 78139904 is about 8839.6778221833. The cubic root of 78139904 is about 427.5211694543.

The spelling of 78139904 in words is "seventy-eight million, one hundred thirty-nine thousand, nine hundred four".