21715510252613 has 4 divisors (see below), whose sum is σ = 22083569748480. Its totient is φ = 21347450756748.

The previous prime is 21715510252559. The next prime is 21715510252619. The reversal of 21715510252613 is 31625201551712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21715510252613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715510252619) 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, 184029747845 + ... + 184029747962.

It is an arithmetic number, because the mean of its divisors is an integer number (5520892437120).

Almost surely, 2^{21715510252613} is an apocalyptic number.

It is an amenable number.

21715510252613 is a deficient number, since it is larger than the sum of its proper divisors (368059495867).

21715510252613 is an equidigital number, since it uses as much as digits as its factorization.

21715510252613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368059495866.

The product of its (nonzero) digits is 126000, while the sum is 41.

The spelling of 21715510252613 in words is "twenty-one trillion, seven hundred fifteen billion, five hundred ten million, two hundred fifty-two thousand, six hundred thirteen".