391721964 has 24 divisors (see below), whose sum is σ = 920998848. Its totient is φ = 129576720.

The previous prime is 391721951. The next prime is 391722011. The reversal of 391721964 is 469127193.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123022 + ... + 126165.

It is an arithmetic number, because the mean of its divisors is an integer number (38374952).

Almost surely, 2^391721964 is an apocalyptic number.

It is an amenable number.

391721964 is an abundant number, since it is smaller than the sum of its proper divisors (529276884).

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

391721964 is a wasteful number, since it uses less digits than its factorization.

391721964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249325 (or 249323 counting only the distinct ones).

The product of its digits is 81648, while the sum is 42.

The square root of 391721964 is about 19791.9671584206. The cubic root of 391721964 is about 731.6880706848.

The spelling of 391721964 in words is "three hundred ninety-one million, seven hundred twenty-one thousand, nine hundred sixty-four".