391979904 has 64 divisors (see below), whose sum is σ = 1045165440. Its totient is φ = 130162176.

The previous prime is 391979881. The next prime is 391979911. The reversal of 391979904 is 409979193.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106869 + ... + 110475.

It is an arithmetic number, because the mean of its divisors is an integer number (16330710).

Almost surely, 2^391979904 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 391979904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (522582720).

391979904 is an abundant number, since it is smaller than the sum of its proper divisors (653185536).

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

391979904 is a wasteful number, since it uses less digits than its factorization.

391979904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3907 (or 3895 counting only the distinct ones).

The product of its (nonzero) digits is 551124, while the sum is 51.

The square root of 391979904 is about 19798.4823660805. The cubic root of 391979904 is about 731.8486354290.

The spelling of 391979904 in words is "three hundred ninety-one million, nine hundred seventy-nine thousand, nine hundred four".