21517171652 has 12 divisors (see below), whose sum is σ = 37907769900. Its totient is φ = 10686380256.

The previous prime is 21517171601. The next prime is 21517171667. The reversal of 21517171652 is 25617171512.

It can be written as a sum of positive squares in 2 ways, for example, as 6473167936 + 15044003716 = 80456^2 + 122654^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18050723 + ... + 18051914.

It is an arithmetic number, because the mean of its divisors is an integer number (3158980825).

Almost surely, 2^21517171652 is an apocalyptic number.

It is an amenable number.

21517171652 is a deficient number, since it is larger than the sum of its proper divisors (16390598248).

21517171652 is a wasteful number, since it uses less digits than its factorization.

21517171652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36102790 (or 36102788 counting only the distinct ones).

The product of its digits is 29400, while the sum is 38.

The spelling of 21517171652 in words is "twenty-one billion, five hundred seventeen million, one hundred seventy-one thousand, six hundred fifty-two".