21525633652513 has 4 divisors (see below), whose sum is σ = 22267896881940. Its totient is φ = 20783370423088.

The previous prime is 21525633652483. The next prime is 21525633652529. The reversal of 21525633652513 is 31525633652512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14046814376464 + 7478819276049 = 3747908^2 + 2734743^2 .

It is a cyclic number.

It is not a de Polignac number, because 21525633652513 - 2²¹ = 21525631555361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525633652543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 371131614670 + ... + 371131614727.

It is an arithmetic number, because the mean of its divisors is an integer number (5566974220485).

Almost surely, 2^{21525633652513} is an apocalyptic number.

It is an amenable number.

21525633652513 is a deficient number, since it is larger than the sum of its proper divisors (742263229427).

21525633652513 is an equidigital number, since it uses as much as digits as its factorization.

21525633652513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742263229426.

The product of its digits is 4860000, while the sum is 49.

Subtracting 21525633652513 from its reverse (31525633652512), we obtain a palindrome (9999999999999).

The spelling of 21525633652513 in words is "twenty-one trillion, five hundred twenty-five billion, six hundred thirty-three million, six hundred fifty-two thousand, five hundred thirteen".