64397440 has 32 divisors (see below), whose sum is σ = 153951660. Its totient is φ = 25758720.

The previous prime is 64397419. The next prime is 64397477. The reversal of 64397440 is 4479346.

It can be written as a sum of positive squares in 2 ways, for example, as 62346816 + 2050624 = 7896^2 + 1432^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 64397440.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49671 + ... + 50950.

Almost surely, 2^64397440 is an apocalyptic number.

It is an amenable number.

64397440 is an abundant number, since it is smaller than the sum of its proper divisors (89554220).

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

64397440 is a wasteful number, since it uses less digits than its factorization.

64397440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100640 (or 100628 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 37.

The square root of 64397440 is about 8024.8015551788. The cubic root of 64397440 is about 400.8262919288.

The spelling of 64397440 in words is "sixty-four million, three hundred ninety-seven thousand, four hundred forty".