21328664580 has 96 divisors (see below), whose sum is σ = 67040090880. Its totient is φ = 5628994560.

The previous prime is 21328664569. The next prime is 21328664587. The reversal of 21328664580 is 8546682312.

21328664580 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 8 + 6 + 64 + 580 = 666.

It is a super-2 number, since 2×21328664580² (a number of 21 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21328664587) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 151216 + ... + 255975.

It is an arithmetic number, because the mean of its divisors is an integer number (698334280).

Almost surely, 2^21328664580 is an apocalyptic number.

21328664580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21328664580 is an abundant number, since it is smaller than the sum of its proper divisors (45711426300).

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

21328664580 is a wasteful number, since it uses less digits than its factorization.

21328664580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407306 (or 407298 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 45.

The spelling of 21328664580 in words is "twenty-one billion, three hundred twenty-eight million, six hundred sixty-four thousand, five hundred eighty".