21723637166 has 48 divisors (see below), whose sum is σ = 41390801712. Its totient is φ = 8455708800.

The previous prime is 21723637151. The next prime is 21723637181. The reversal of 21723637166 is 66173632712.

It is an interprime number because it is at equal distance from previous prime (21723637151) and next prime (21723637181).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1195106 + ... + 1213146.

It is an arithmetic number, because the mean of its divisors is an integer number (862308369).

Almost surely, 2^21723637166 is an apocalyptic number.

21723637166 is a deficient number, since it is larger than the sum of its proper divisors (19667164546).

21723637166 is a wasteful number, since it uses less digits than its factorization.

21723637166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19185 (or 19178 counting only the distinct ones).

The product of its digits is 381024, while the sum is 44.

The spelling of 21723637166 in words is "twenty-one billion, seven hundred twenty-three million, six hundred thirty-seven thousand, one hundred sixty-six".