21615106560 has 160 divisors (see below), whose sum is σ = 69192446400. Its totient is φ = 5756387328.

The previous prime is 21615106511. The next prime is 21615106661. The reversal of 21615106560 is 6560151612.

It is a tau number, because it is divible by the number of its divisors (160).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8054979 + ... + 8057661.

It is an arithmetic number, because the mean of its divisors is an integer number (432452790).

Almost surely, 2^21615106560 is an apocalyptic number.

21615106560 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 21615106560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34596223200).

21615106560 is an abundant number, since it is smaller than the sum of its proper divisors (47577339840).

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

21615106560 is a wasteful number, since it uses less digits than its factorization.

21615106560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3758 (or 3742 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 33.

The spelling of 21615106560 in words is "twenty-one billion, six hundred fifteen million, one hundred six thousand, five hundred sixty".