21520623574617 has 32 divisors (see below), whose sum is σ = 30514546851840. Its totient is φ = 13444271796480.

The previous prime is 21520623574591. The next prime is 21520623574699. The reversal of 21520623574617 is 71647532602512.

It is not a de Polignac number, because 21520623574617 - 2¹⁴ = 21520623558233 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 21520623574617.

It is not an unprimeable number, because it can be changed into a prime (21520623574717) 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, 70434058 + ... + 70738940.

It is an arithmetic number, because the mean of its divisors is an integer number (953579589120).

Almost surely, 2^{21520623574617} is an apocalyptic number.

It is an amenable number.

21520623574617 is a deficient number, since it is larger than the sum of its proper divisors (8993923277223).

21520623574617 is a wasteful number, since it uses less digits than its factorization.

21520623574617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310933.

The product of its (nonzero) digits is 4233600, while the sum is 51.

The spelling of 21520623574617 in words is "twenty-one trillion, five hundred twenty billion, six hundred twenty-three million, five hundred seventy-four thousand, six hundred seventeen".