64400557 has 16 divisors (see below), whose sum is σ = 73615360. Its totient is φ = 55847232.

The previous prime is 64400551. The next prime is 64400587. The reversal of 64400557 is 75500446.

It is a happy number.

It is not a de Polignac number, because 64400557 - 2¹⁵ = 64367789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64400551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30343 + ... + 32395.

It is an arithmetic number, because the mean of its divisors is an integer number (4600960).

Almost surely, 2^64400557 is an apocalyptic number.

It is an amenable number.

64400557 is a deficient number, since it is larger than the sum of its proper divisors (9214803).

64400557 is a wasteful number, since it uses less digits than its factorization.

64400557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2212.

The product of its (nonzero) digits is 16800, while the sum is 31.

The square root of 64400557 is about 8024.9957632388. The cubic root of 64400557 is about 400.8327588287.

The spelling of 64400557 in words is "sixty-four million, four hundred thousand, five hundred fifty-seven".