21153774172 has 18 divisors (see below), whose sum is σ = 38251797864. Its totient is φ = 10235695320.

The previous prime is 21153774157. The next prime is 21153774179. The reversal of 21153774172 is 27147735112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153774179) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2747688 + ... + 2755375.

Almost surely, 2^21153774172 is an apocalyptic number.

It is an amenable number.

21153774172 is a deficient number, since it is larger than the sum of its proper divisors (17098023692).

21153774172 is a wasteful number, since it uses less digits than its factorization.

21153774172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5503129 (or 5503096 counting only the distinct ones).

The product of its digits is 82320, while the sum is 40.

The spelling of 21153774172 in words is "twenty-one billion, one hundred fifty-three million, seven hundred seventy-four thousand, one hundred seventy-two".