64639128 has 32 divisors (see below), whose sum is σ = 163114560. Its totient is φ = 21344160.

The previous prime is 64639073. The next prime is 64639129. The reversal of 64639128 is 82193646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64639129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10018 + ... + 15153.

It is an arithmetic number, because the mean of its divisors is an integer number (5097330).

Almost surely, 2^64639128 is an apocalyptic number.

It is an amenable number.

64639128 is an abundant number, since it is smaller than the sum of its proper divisors (98475432).

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

64639128 is a wasteful number, since it uses less digits than its factorization.

64639128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25287 (or 25283 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 64639128 is about 8039.8462671870. The cubic root of 64639128 is about 401.3271087531.

The spelling of 64639128 in words is "sixty-four million, six hundred thirty-nine thousand, one hundred twenty-eight".