491809920 has 512 divisors, whose sum is σ = 1964666880. Its totient is φ = 102187008.

The previous prime is 491809907. The next prime is 491809931. The reversal of 491809920 is 29908194.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11437419 + ... + 11437461.

It is an arithmetic number, because the mean of its divisors is an integer number (3837240).

Almost surely, 2^491809920 is an apocalyptic number.

491809920 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 491809920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (982333440).

491809920 is an abundant number, since it is smaller than the sum of its proper divisors (1472856960).

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

491809920 is a wasteful number, since it uses less digits than its factorization.

491809920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 491809920 is about 22176.7878647923. The cubic root of 491809920 is about 789.3429991309.

The spelling of 491809920 in words is "four hundred ninety-one million, eight hundred nine thousand, nine hundred twenty".