21615266751617 has 32 divisors (see below), whose sum is σ = 27921637785600. Its totient is φ = 16239146011200.

The previous prime is 21615266751571. The next prime is 21615266751623. The reversal of 21615266751617 is 71615766251612.

It is not a de Polignac number, because 21615266751617 - 2¹⁸ = 21615266489473 is a prime.

It is a super-2 number, since 2×21615266751617² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21615266751017) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16189517 + ... + 17473722.

It is an arithmetic number, because the mean of its divisors is an integer number (872551180800).

Almost surely, 2^{21615266751617} is an apocalyptic number.

It is an amenable number.

21615266751617 is a deficient number, since it is larger than the sum of its proper divisors (6306371033983).

21615266751617 is a wasteful number, since it uses less digits than its factorization.

21615266751617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33663557.

The product of its digits is 6350400, while the sum is 56.

The spelling of 21615266751617 in words is "twenty-one trillion, six hundred fifteen billion, two hundred sixty-six million, seven hundred fifty-one thousand, six hundred seventeen".