21595772025 has 81 divisors (see below), whose sum is σ = 39474100263. Its totient is φ = 11286144000.

The previous prime is 21595771991. The next prime is 21595772069. The reversal of 21595772025 is 52027759512.

The square root of 21595772025 is 146955.

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

21595772025 is a `hidden beast` number, since 2 + 1 + 59 + 577 + 2 + 0 + 25 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 3156304761 + 18439467264 = 56181^2 + 135792^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21595772025 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 213819475 + ... + 213819575.

Almost surely, 2^21595772025 is an apocalyptic number.

21595772025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21595772025 is the 146955-th square number.

21595772025 is the 73478-th centered octagonal number.

It is an amenable number.

21595772025 is a deficient number, since it is larger than the sum of its proper divisors (17878328238).

21595772025 is an equidigital number, since it uses as much as digits as its factorization.

21595772025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 441000, while the sum is 45.

The spelling of 21595772025 in words is "twenty-one billion, five hundred ninety-five million, seven hundred seventy-two thousand, twenty-five".