391939880 has 32 divisors (see below), whose sum is σ = 894291840. Its totient is φ = 154566720.

The previous prime is 391939871. The next prime is 391939903. The reversal of 391939880 is 88939193.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66164 + ... + 71843.

It is an arithmetic number, because the mean of its divisors is an integer number (27946620).

Almost surely, 2^391939880 is an apocalyptic number.

It is an amenable number.

391939880 is an abundant number, since it is smaller than the sum of its proper divisors (502351960).

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

391939880 is a wasteful number, since it uses less digits than its factorization.

391939880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138089 (or 138085 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 391939880 is about 19797.4715557316. The cubic root of 391939880 is about 731.8237255578.

The spelling of 391939880 in words is "three hundred ninety-one million, nine hundred thirty-nine thousand, eight hundred eighty".