491908040 has 64 divisors (see below), whose sum is σ = 1194404400. Its totient is φ = 181251072.

The previous prime is 491908009. The next prime is 491908069. The reversal of 491908040 is 40809194.

It is a Cunningham number, because it is equal to 22179²-1.

It can be written as a sum of positive squares in 8 ways, for example, as 3232804 + 488675236 = 1798^2 + 22106^2 .

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, 443006 + ... + 444114.

Almost surely, 2^491908040 is an apocalyptic number.

491908040 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 491908040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (597202200).

491908040 is an abundant number, since it is smaller than the sum of its proper divisors (702496360).

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

491908040 is a wasteful number, since it uses less digits than its factorization.

491908040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1986 (or 1982 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 491908040 is about 22178.9999774562. Note that the first 4 decimals coincide. The cubic root of 491908040 is about 789.3954890474.

The spelling of 491908040 in words is "four hundred ninety-one million, nine hundred eight thousand, forty".