21515445525136 has 160 divisors (see below), whose sum is σ = 44759278080000. Its totient is φ = 9989180328960.

The previous prime is 21515445525121. The next prime is 21515445525143. The reversal of 21515445525136 is 63152554451512.

It is a super-2 number, since 2×21515445525136² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21515445525136.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3399498420 + ... + 3399504748.

It is an arithmetic number, because the mean of its divisors is an integer number (279745488000).

Almost surely, 2^{21515445525136} 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 21515445525136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22379639040000).

21515445525136 is an abundant number, since it is smaller than the sum of its proper divisors (23243832554864).

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

21515445525136 is a wasteful number, since it uses less digits than its factorization.

21515445525136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7325 (or 7319 counting only the distinct ones).

The product of its digits is 3600000, while the sum is 49.

Adding to 21515445525136 its reverse (63152554451512), we get a palindrome (84667999976648).

The spelling of 21515445525136 in words is "twenty-one trillion, five hundred fifteen billion, four hundred forty-five million, five hundred twenty-five thousand, one hundred thirty-six".