491991320 has 32 divisors (see below), whose sum is σ = 1165244400. Its totient is φ = 186438528.

The previous prime is 491991317. The next prime is 491991389. The reversal of 491991320 is 23199194.

It is a Harshad number since it is a multiple of its sum of digits (38).

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 7 ways as a sum of consecutive naturals, for example, 322919 + ... + 324438.

Almost surely, 2^491991320 is an apocalyptic number.

491991320 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

491991320 is an abundant number, since it is smaller than the sum of its proper divisors (673253080).

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

491991320 is a wasteful number, since it uses less digits than its factorization.

491991320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647387 (or 647383 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 491991320 is about 22180.8773496451. The cubic root of 491991320 is about 789.4400347358.

The spelling of 491991320 in words is "four hundred ninety-one million, nine hundred ninety-one thousand, three hundred twenty".