21256182025 has 27 divisors (see below), whose sum is σ = 28553871189. Its totient is φ = 15689874720.

The previous prime is 21256182023. The next prime is 21256182029. The reversal of 21256182025 is 52028165212.

The square root of 21256182025 is 145795.

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 5478812361 + 15777369664 = 74019^2 + 125608^2 .

It is not a de Polignac number, because 21256182025 - 2¹ = 21256182023 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21256182023) by changing a digit.

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, 9475554 + ... + 9477796.

Almost surely, 2^21256182025 is an apocalyptic number.

21256182025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21256182025 is the 145795-th square number.

21256182025 is the 72898-th centered octagonal number.

It is an amenable number.

21256182025 is a deficient number, since it is larger than the sum of its proper divisors (7297689164).

21256182025 is an frugal number, since it uses more digits than its factorization.

21256182025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4522 (or 2261 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 34.

The spelling of 21256182025 in words is "twenty-one billion, two hundred fifty-six million, one hundred eighty-two thousand, twenty-five".