21120656613516 has 216 divisors, whose sum is σ = 55641793085424. Its totient is φ = 6752617148160.

The previous prime is 21120656613493. The next prime is 21120656613523. The reversal of 21120656613516 is 61531665602112.

21120656613516 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 0 + 65 + 66 + 13 + 516 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4471870731 + ... + 4471875453.

It is an arithmetic number, because the mean of its divisors is an integer number (257600893914).

Almost surely, 2^{21120656613516} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120656613516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27820896542712).

21120656613516 is an abundant number, since it is smaller than the sum of its proper divisors (34521136471908).

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

21120656613516 is a wasteful number, since it uses less digits than its factorization.

21120656613516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5941 (or 5889 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 21120656613516 in words is "twenty-one trillion, one hundred twenty billion, six hundred fifty-six million, six hundred thirteen thousand, five hundred sixteen".