183988665721 has 27 divisors (see below), whose sum is σ = 221767340301. Its totient is φ = 152194420224.

The previous prime is 183988665703. The next prime is 183988665743. The reversal of 183988665721 is 127566889381.

The square root of 183988665721 is 428939.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 81867515625 + 102121150096 = 286125^2 + 319564^2 .

It is not a de Polignac number, because 183988665721 - 2⁵ = 183988665689 is a prime.

It is a super-2 number, since 2×183988665721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (183988665701) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 87073561 + ... + 87075673.

Almost surely, 2^183988665721 is an apocalyptic number.

183988665721 is the 428939-th square number.

183988665721 is the 214470-th centered octagonal number.

It is an amenable number.

183988665721 is a deficient number, since it is larger than the sum of its proper divisors (37778674580).

183988665721 is an frugal number, since it uses more digits than its factorization.

183988665721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4298 (or 2149 counting only the distinct ones).

The product of its digits is 34836480, while the sum is 64.

Multiplying 183988665721 by its sum of digits (64), we get a square (11775274606144 = 3431512²).

The spelling of 183988665721 in words is "one hundred eighty-three billion, nine hundred eighty-eight million, six hundred sixty-five thousand, seven hundred twenty-one".