21613186560 has 480 divisors, whose sum is σ = 81504783360. Its totient is φ = 4870914048.

The previous prime is 21613186523. The next prime is 21613186571. The reversal of 21613186560 is 6568131612.

It is a tau number, because it is divible by the number of its divisors (480).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 29728917 + ... + 29729643.

It is an arithmetic number, because the mean of its divisors is an integer number (169801632).

Almost surely, 2^21613186560 is an apocalyptic number.

21613186560 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 21613186560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40752391680).

21613186560 is an abundant number, since it is smaller than the sum of its proper divisors (59891596800).

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

21613186560 is an equidigital number, since it uses as much as digits as its factorization.

21613186560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846 (or 823 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The spelling of 21613186560 in words is "twenty-one billion, six hundred thirteen million, one hundred eighty-six thousand, five hundred sixty".