21513420113525 has 6 divisors (see below), whose sum is σ = 26676640940802. Its totient is φ = 17210736090800.

The previous prime is 21513420113501. The next prime is 21513420113543. The reversal of 21513420113525 is 52531102431512.

It can be written as a sum of positive squares in 3 ways, for example, as 7675548348484 + 13837871765041 = 2770478^2 + 3719929^2 .

It is not a de Polignac number, because 21513420113525 - 2²⁴ = 21513403336309 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 430268402246 + ... + 430268402295.

It is an arithmetic number, because the mean of its divisors is an integer number (4446106823467).

Almost surely, 2^{21513420113525} is an apocalyptic number.

21513420113525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21513420113525 is a deficient number, since it is larger than the sum of its proper divisors (5163220827277).

21513420113525 is an equidigital number, since it uses as much as digits as its factorization.

21513420113525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860536804551 (or 860536804546 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 21513420113525 in words is "twenty-one trillion, five hundred thirteen billion, four hundred twenty million, one hundred thirteen thousand, five hundred twenty-five".