491581440 has 416 divisors, whose sum is σ = 2013020160. Its totient is φ = 111476736.

The previous prime is 491581429. The next prime is 491581457. The reversal of 491581440 is 44185194.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 491581395 and 491581404.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 3870657 + ... + 3870783.

Almost surely, 2^491581440 is an apocalyptic number.

491581440 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 491581440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1006510080).

491581440 is an abundant number, since it is smaller than the sum of its proper divisors (1521438720).

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

491581440 is a wasteful number, since it uses less digits than its factorization.

491581440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 491581440 is about 22171.6359342291. The cubic root of 491581440 is about 789.2207452434.

The spelling of 491581440 in words is "four hundred ninety-one million, five hundred eighty-one thousand, four hundred forty".