21804952225 has 27 divisors (see below), whose sum is σ = 31459987827. Its totient is φ = 14948423280.

The previous prime is 21804952217. The next prime is 21804952231. The reversal of 21804952225 is 52225940812.

The square root of 21804952225 is 147665.

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., 7849782801 + 13955169424 = 88599^2 + 118132^2 .

It is not a de Polignac number, because 21804952225 - 2³ = 21804952217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 5166166 + ... + 5170384.

Almost surely, 2^21804952225 is an apocalyptic number.

21804952225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21804952225 is the 147665-th square number.

21804952225 is the 73833-rd centered octagonal number.

It is an amenable number.

21804952225 is a deficient number, since it is larger than the sum of its proper divisors (9655035602).

21804952225 is an frugal number, since it uses more digits than its factorization.

21804952225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8462 (or 4231 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 40.

The spelling of 21804952225 in words is "twenty-one billion, eight hundred four million, nine hundred fifty-two thousand, two hundred twenty-five".