491681440 has 36 divisors (see below), whose sum is σ = 1162260414. Its totient is φ = 196560384.

The previous prime is 491681431. The next prime is 491681447. The reversal of 491681440 is 44186194.

It can be written as a sum of positive squares in 3 ways, for example, as 109244304 + 382437136 = 10452^2 + 19556^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 491681440.

It is not an unprimeable number, because it can be changed into a prime (491681447) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 279604 + ... + 281356.

Almost surely, 2^491681440 is an apocalyptic number.

491681440 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

491681440 is an abundant number, since it is smaller than the sum of its proper divisors (670578974).

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

491681440 is an frugal number, since it uses more digits than its factorization.

491681440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3521 (or 1760 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 491681440 is about 22173.8909531007. The cubic root of 491681440 is about 789.2742573827.

The spelling of 491681440 in words is "four hundred ninety-one million, six hundred eighty-one thousand, four hundred forty".