391868928 has 200 divisors, whose sum is σ = 1277440560. Its totient is φ = 118609920.

The previous prime is 391868927. The next prime is 391868987. The reversal of 391868928 is 829868193.

It is a happy number.

It is a super-2 number, since 2×391868928² = 307122513463738368, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (391868927) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 455763 + ... + 456621.

Almost surely, 2^391868928 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 391868928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (638720280).

391868928 is an abundant number, since it is smaller than the sum of its proper divisors (885571632).

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

391868928 is an equidigital number, since it uses as much as digits as its factorization.

391868928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900 (or 875 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 54.

The square root of 391868928 is about 19795.6795286244. The cubic root of 391868928 is about 731.7795627553.

The spelling of 391868928 in words is "three hundred ninety-one million, eight hundred sixty-eight thousand, nine hundred twenty-eight".