57991440 has 80 divisors (see below), whose sum is σ = 193612608. Its totient is φ = 14274048.

The previous prime is 57991411. The next prime is 57991447. The reversal of 57991440 is 4419975.

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

It is a super-2 number, since 2×57991440² = 6726014226547200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (57991447) by changing a digit.

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, 6174 + ... + 12413.

Almost surely, 2^57991440 is an apocalyptic number.

It is an amenable number.

57991440 is an abundant number, since it is smaller than the sum of its proper divisors (135621168).

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

57991440 is a wasteful number, since it uses less digits than its factorization.

57991440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18616 (or 18610 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 57991440 is about 7615.2110935942. The cubic root of 57991440 is about 387.0686201925.

The spelling of 57991440 in words is "fifty-seven million, nine hundred ninety-one thousand, four hundred forty".