21675651172 has 18 divisors (see below), whose sum is σ = 44125433142. Its totient is φ = 9289564704.

The previous prime is 21675651161. The next prime is 21675651187. The reversal of 21675651172 is 27115657612.

It can be written as a sum of positive squares in only one way, i.e., 12556547136 + 9119104036 = 112056^2 + 95494^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 55294833 + ... + 55295224.

Almost surely, 2^21675651172 is an apocalyptic number.

It is an amenable number.

21675651172 is an abundant number, since it is smaller than the sum of its proper divisors (22449781970).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21675651172 is a wasteful number, since it uses less digits than its factorization.

21675651172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110590075 (or 110590066 counting only the distinct ones).

The product of its digits is 176400, while the sum is 43.

The spelling of 21675651172 in words is "twenty-one billion, six hundred seventy-five million, six hundred fifty-one thousand, one hundred seventy-two".