21715555424327 has 4 divisors (see below), whose sum is σ = 21721057215816. Its totient is φ = 21710053632840.

The previous prime is 21715555424267. The next prime is 21715555424333. The reversal of 21715555424327 is 72342455551712.

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

It is a cyclic number.

It is not a de Polignac number, because 21715555424327 - 2²⁶ = 21715488315463 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 (21715555423327) 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, 2750889824 + ... + 2750897717.

It is an arithmetic number, because the mean of its divisors is an integer number (5430264303954).

Almost surely, 2^{21715555424327} is an apocalyptic number.

21715555424327 is a deficient number, since it is larger than the sum of its proper divisors (5501791489).

21715555424327 is an equidigital number, since it uses as much as digits as its factorization.

21715555424327 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5501791488.

The product of its digits is 11760000, while the sum is 53.

The spelling of 21715555424327 in words is "twenty-one trillion, seven hundred fifteen billion, five hundred fifty-five million, four hundred twenty-four thousand, three hundred twenty-seven".