21272525 has 12 divisors (see below), whose sum is σ = 27930132. Its totient is φ = 16016640.

The previous prime is 21272507. The next prime is 21272527. The reversal of 21272525 is 52527212.

It can be written as a sum of positive squares in 6 ways, for example, as 2079364 + 19193161 = 1442^2 + 4381^2 .

It is not a de Polignac number, because 21272525 - 2⁸ = 21272269 is a prime.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21272494 and 21272503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21272527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24602 + ... + 25451.

It is an arithmetic number, because the mean of its divisors is an integer number (2327511).

Almost surely, 2^21272525 is an apocalyptic number.

21272525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21272525 is a deficient number, since it is larger than the sum of its proper divisors (6657607).

21272525 is a wasteful number, since it uses less digits than its factorization.

21272525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50080 (or 50075 counting only the distinct ones).

The product of its digits is 2800, while the sum is 26.

The square root of 21272525 is about 4612.2147608280. The cubic root of 21272525 is about 277.0807455742.

Adding to 21272525 its reverse (52527212), we get a palindrome (73799737).

The spelling of 21272525 in words is "twenty-one million, two hundred seventy-two thousand, five hundred twenty-five".