491205840 has 80 divisors (see below), whose sum is σ = 1527866496. Its totient is φ = 130547200.

The previous prime is 491205839. The next prime is 491205859. The reversal of 491205840 is 48502194.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71350 + ... + 77930.

Almost surely, 2^491205840 is an apocalyptic number.

491205840 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 491205840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (763933248).

491205840 is an abundant number, since it is smaller than the sum of its proper divisors (1036660656).

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

491205840 is a wasteful number, since it uses less digits than its factorization.

491205840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6908 (or 6902 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 491205840 is about 22163.1640340453. The cubic root of 491205840 is about 789.0196888043.

The spelling of 491205840 in words is "four hundred ninety-one million, two hundred five thousand, eight hundred forty".