491997440 has 144 divisors (see below), whose sum is σ = 1304202816. Its totient is φ = 176332800.

The previous prime is 491997437. The next prime is 491997487. The reversal of 491997440 is 44799194.

It is a super-2 number, since 2×491997440² = 484122961933107200, which contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 1168430 + ... + 1168850.

It is an arithmetic number, because the mean of its divisors is an integer number (9056964).

Almost surely, 2^491997440 is an apocalyptic number.

491997440 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 491997440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (652101408).

491997440 is an abundant number, since it is smaller than the sum of its proper divisors (812205376).

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

491997440 is a wasteful number, since it uses less digits than its factorization.

491997440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536 (or 522 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 491997440 is about 22181.0153058871. The cubic root of 491997440 is about 789.4433080679.

The spelling of 491997440 in words is "four hundred ninety-one million, nine hundred ninety-seven thousand, four hundred forty".