491579638 has 36 divisors (see below), whose sum is σ = 838239948. Its totient is φ = 214416720.

The previous prime is 491579593. The next prime is 491579657. The reversal of 491579638 is 836975194.

It is a happy number.

It is a super-2 number, since 2×491579638² = 483301080992422088, which contains 22 as substring.

It is a congruent number.

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 17 ways as a sum of consecutive naturals, for example, 3015745 + ... + 3015907.

It is an arithmetic number, because the mean of its divisors is an integer number (23284443).

Almost surely, 2^491579638 is an apocalyptic number.

491579638 is a deficient number, since it is larger than the sum of its proper divisors (346660310).

491579638 is a wasteful number, since it uses less digits than its factorization.

491579638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 205 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 52.

The square root of 491579638 is about 22171.5952966854. The cubic root of 491579638 is about 789.2197808881.

The spelling of 491579638 in words is "four hundred ninety-one million, five hundred seventy-nine thousand, six hundred thirty-eight".