21189864530025 has 27 divisors (see below), whose sum is σ = 37953525476919. Its totient is φ = 11301224256720.

The previous prime is 21189864530017. The next prime is 21189864530083. The reversal of 21189864530025 is 52003546898112.

The square root of 21189864530025 is 4603245.

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

21189864530025 is a `hidden beast` number, since 2 + 1 + 1 + 8 + 9 + 86 + 4 + 530 + 0 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 7628351230809 + 13561513299216 = 2761947^2 + 3682596^2 .

It is not a de Polignac number, because 21189864530025 - 2³ = 21189864530017 is a prime.

It is a super-2 number, since 2×21189864530025² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 68895234 + ... + 69202116.

Almost surely, 2^{21189864530025} is an apocalyptic number.

21189864530025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21189864530025 is the 4603245-th square number.

21189864530025 is the 2301623-rd centered octagonal number.

It is an amenable number.

21189864530025 is a deficient number, since it is larger than the sum of its proper divisors (16763660946894).

21189864530025 is an frugal number, since it uses more digits than its factorization.

21189864530025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 613782 (or 306891 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 54.

The spelling of 21189864530025 in words is "twenty-one trillion, one hundred eighty-nine billion, eight hundred sixty-four million, five hundred thirty thousand, twenty-five".