21660521160 has 128 divisors (see below), whose sum is σ = 65751552000. Its totient is φ = 5708102400.

The previous prime is 21660521137. The next prime is 21660521177. The reversal of 21660521160 is 6112506612.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3602877 + ... + 3608883.

It is an arithmetic number, because the mean of its divisors is an integer number (513684000).

Almost surely, 2^21660521160 is an apocalyptic number.

21660521160 is a gapful number since it is divisible by the number (20) 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 21660521160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32875776000).

21660521160 is an abundant number, since it is smaller than the sum of its proper divisors (44091030840).

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

21660521160 is a wasteful number, since it uses less digits than its factorization.

21660521160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6371 (or 6367 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The spelling of 21660521160 in words is "twenty-one billion, six hundred sixty million, five hundred twenty-one thousand, one hundred sixty".