64644632728 has 16 divisors (see below), whose sum is σ = 130532431680. Its totient is φ = 29835984288.

The previous prime is 64644632713. The next prime is 64644632791. The reversal of 64644632728 is 82723644646.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 310791400 + ... + 310791607.

It is an arithmetic number, because the mean of its divisors is an integer number (8158276980).

Almost surely, 2^64644632728 is an apocalyptic number.

It is an amenable number.

64644632728 is an abundant number, since it is smaller than the sum of its proper divisors (65887798952).

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

64644632728 is a wasteful number, since it uses less digits than its factorization.

64644632728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621583026 (or 621583022 counting only the distinct ones).

The product of its digits is 9289728, while the sum is 52.

The spelling of 64644632728 in words is "sixty-four billion, six hundred forty-four million, six hundred thirty-two thousand, seven hundred twenty-eight".