64621537920 has 192 divisors, whose sum is σ = 223603380000. Its totient is φ = 17197111296.

The previous prime is 64621537919. The next prime is 64621537957. The reversal of 64621537920 is 2973512646.

64621537920 is a `hidden beast` number, since 6 + 4 + 6 + 21 + 537 + 92 + 0 = 666.

64621537920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2862999 + ... + 2885481.

Almost surely, 2^64621537920 is an apocalyptic number.

64621537920 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 64621537920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111801690000).

64621537920 is an abundant number, since it is smaller than the sum of its proper divisors (158981842080).

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

64621537920 is a wasteful number, since it uses less digits than its factorization.

64621537920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23007 (or 22992 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 64621537920 in words is "sixty-four billion, six hundred twenty-one million, five hundred thirty-seven thousand, nine hundred twenty".