64638657 has 12 divisors (see below), whose sum is σ = 94492944. Its totient is φ = 42572760.

The previous prime is 64638647. The next prime is 64638659. The reversal of 64638657 is 75683646.

64638657 is a `hidden beast` number, since 6 + 4 + 638 + 6 + 5 + 7 = 666.

It is not a de Polignac number, because 64638657 - 2⁸ = 64638401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64638659) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42519 + ... + 44012.

It is an arithmetic number, because the mean of its divisors is an integer number (7874412).

Almost surely, 2^64638657 is an apocalyptic number.

It is an amenable number.

64638657 is a deficient number, since it is larger than the sum of its proper divisors (29854287).

64638657 is a wasteful number, since it uses less digits than its factorization.

64638657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86620 (or 86617 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The square root of 64638657 is about 8039.8169755287. The cubic root of 64638657 is about 401.3261339796.

The spelling of 64638657 in words is "sixty-four million, six hundred thirty-eight thousand, six hundred fifty-seven".