391489920 has 96 divisors (see below), whose sum is σ = 1351883520. Its totient is φ = 104395776.

The previous prime is 391489913. The next prime is 391489997. The reversal of 391489920 is 29984193.

It is a tau number, because it is divible by the number of its divisors (96).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 11 ways as a sum of consecutive naturals, for example, 28224 + ... + 39743.

It is an arithmetic number, because the mean of its divisors is an integer number (14082120).

Almost surely, 2^391489920 is an apocalyptic number.

391489920 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

391489920 is an abundant number, since it is smaller than the sum of its proper divisors (960393600).

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

391489920 is a wasteful number, since it uses less digits than its factorization.

391489920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67992 (or 67977 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 391489920 is about 19786.1042148271. The cubic root of 391489920 is about 731.5435656717.

The spelling of 391489920 in words is "three hundred ninety-one million, four hundred eighty-nine thousand, nine hundred twenty".