391490988 has 36 divisors (see below), whose sum is σ = 1062619992. Its totient is φ = 111854400.

The previous prime is 391490941. The next prime is 391490989. The reversal of 391490988 is 889094193.

It is a happy number.

It is a super-2 number, since 2×391490988² = 306530387370432288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 391490988.

It is not an unprimeable number, because it can be changed into a prime (391490989) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 332313 + ... + 333488.

It is an arithmetic number, because the mean of its divisors is an integer number (29517222).

Almost surely, 2^391490988 is an apocalyptic number.

It is an amenable number.

391490988 is an abundant number, since it is smaller than the sum of its proper divisors (671129004).

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

391490988 is a wasteful number, since it uses less digits than its factorization.

391490988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665822 (or 665813 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 51.

The square root of 391490988 is about 19786.1312034465. The cubic root of 391490988 is about 731.5442308977.

The spelling of 391490988 in words is "three hundred ninety-one million, four hundred ninety thousand, nine hundred eighty-eight".