21884764225 has 9 divisors (see below), whose sum is σ = 27138024867. Its totient is φ = 17507219640.

The previous prime is 21884764219. The next prime is 21884764261. The reversal of 21884764225 is 52246748812.

The square root of 21884764225 is 147935.

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

It can be written as a sum of positive squares in only one way, i.e., 7878515121 + 14006249104 = 88761^2 + 118348^2 .

It is not a de Polignac number, because 21884764225 - 2⁵ = 21884764193 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 724882 + ... + 754468.

Almost surely, 2^21884764225 is an apocalyptic number.

21884764225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21884764225 is the 147935-th square number.

21884764225 is the 73968-th centered octagonal number.

It is an amenable number.

21884764225 is a deficient number, since it is larger than the sum of its proper divisors (5253260642).

21884764225 is an frugal number, since it uses more digits than its factorization.

21884764225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59184 (or 29592 counting only the distinct ones).

The product of its digits is 1720320, while the sum is 49.

Multiplying 21884764225 by its sum of digits (49), we get a square (1072353447025 = 1035545²).

The spelling of 21884764225 in words is "twenty-one billion, eight hundred eighty-four million, seven hundred sixty-four thousand, two hundred twenty-five".