21445187525 has 12 divisors (see below), whose sum is σ = 27509000100. Its totient is φ = 16564558080.

The previous prime is 21445187521. The next prime is 21445187527. The reversal of 21445187525 is 52578154412.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 4717903969 + 16727283556 = 68687^2 + 129334^2 .

It is not a de Polignac number, because 21445187525 - 2² = 21445187521 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445187521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14789060 + ... + 14790509.

It is an arithmetic number, because the mean of its divisors is an integer number (2292416675).

Almost surely, 2^21445187525 is an apocalyptic number.

21445187525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21445187525 is a deficient number, since it is larger than the sum of its proper divisors (6063812575).

21445187525 is a wasteful number, since it uses less digits than its factorization.

21445187525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29579608 (or 29579603 counting only the distinct ones).

The product of its digits is 448000, while the sum is 44.

The spelling of 21445187525 in words is "twenty-one billion, four hundred forty-five million, one hundred eighty-seven thousand, five hundred twenty-five".