64656385920 has 768 divisors, whose sum is σ = 280467360000. Its totient is φ = 13997297664.

The previous prime is 64656385909. The next prime is 64656385949. The reversal of 64656385920 is 2958365646.

64656385920 is a `hidden beast` number, since 6 + 4 + 6 + 563 + 8 + 59 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 16085671 + ... + 16089689.

It is an arithmetic number, because the mean of its divisors is an integer number (365191875).

Almost surely, 2^64656385920 is an apocalyptic number.

64656385920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64656385920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140233680000).

64656385920 is an abundant number, since it is smaller than the sum of its proper divisors (215810974080).

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

64656385920 is a wasteful number, since it uses less digits than its factorization.

64656385920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080 (or 4055 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 54.

The spelling of 64656385920 in words is "sixty-four billion, six hundred fifty-six million, three hundred eighty-five thousand, nine hundred twenty".