3957638640 has 40 divisors (see below), whose sum is σ = 12268680528. Its totient is φ = 1055370240.

The previous prime is 3957638621. The next prime is 3957638677. The reversal of 3957638640 is 468367593.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8244841 + ... + 8245320.

Almost surely, 2^3957638640 is an apocalyptic number.

3957638640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

3957638640 is an abundant number, since it is smaller than the sum of its proper divisors (8311041888).

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

3957638640 is a wasteful number, since it uses less digits than its factorization.

3957638640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16490177 (or 16490171 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 51.

The square root of 3957638640 is about 62909.7658555490. The cubic root of 3957638640 is about 1581.7774474191. Note that the first 3 decimals are identical.

The spelling of 3957638640 in words is "three billion, nine hundred fifty-seven million, six hundred thirty-eight thousand, six hundred forty".