64320021860 has 24 divisors (see below), whose sum is σ = 135077482680. Its totient is φ = 25726973184.

The previous prime is 64320021859. The next prime is 64320021869. The reversal of 64320021860 is 6812002346.

It can be written as a sum of positive squares in 4 ways, for example, as 10886000896 + 53434020964 = 104336^2 + 231158^2 .

It is not an unprimeable number, because it can be changed into a prime (64320021869) 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, 622622 + ... + 718538.

It is an arithmetic number, because the mean of its divisors is an integer number (5628228445).

Almost surely, 2^64320021860 is an apocalyptic number.

It is an amenable number.

64320021860 is an abundant number, since it is smaller than the sum of its proper divisors (70757460820).

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

64320021860 is a wasteful number, since it uses less digits than its factorization.

64320021860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129455 (or 129453 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 64320021860 in words is "sixty-four billion, three hundred twenty million, twenty-one thousand, eight hundred sixty".