21115525356520 has 64 divisors (see below), whose sum is σ = 55217354486400. Its totient is φ = 7116903456000.

The previous prime is 21115525356451. The next prime is 21115525356521. The reversal of 21115525356520 is 2565352551112.

It is a super-2 number, since 2×21115525356520² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21115525356521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 639073231 + ... + 639106270.

It is an arithmetic number, because the mean of its divisors is an integer number (862771163850).

Almost surely, 2^{21115525356520} is an apocalyptic number.

21115525356520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115525356520 is an abundant number, since it is smaller than the sum of its proper divisors (34101829129880).

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

21115525356520 is a wasteful number, since it uses less digits than its factorization.

21115525356520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1278179578 (or 1278179574 counting only the distinct ones).

The product of its (nonzero) digits is 450000, while the sum is 43.

The spelling of 21115525356520 in words is "twenty-one trillion, one hundred fifteen billion, five hundred twenty-five million, three hundred fifty-six thousand, five hundred twenty".