21547252 has 12 divisors (see below), whose sum is σ = 37754500. Its totient is φ = 10760256.

The previous prime is 21547243. The next prime is 21547259. The reversal of 21547252 is 25274512.

It can be written as a sum of positive squares in 2 ways, for example, as 698896 + 20848356 = 836^2 + 4566^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21547252.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21547259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 874 + ... + 6622.

Almost surely, 2^21547252 is an apocalyptic number.

It is an amenable number.

21547252 is a deficient number, since it is larger than the sum of its proper divisors (16207248).

21547252 is a wasteful number, since it uses less digits than its factorization.

21547252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6690 (or 6688 counting only the distinct ones).

The product of its digits is 5600, while the sum is 28.

The square root of 21547252 is about 4641.9017654405. The cubic root of 21547252 is about 278.2684465937.

The spelling of 21547252 in words is "twenty-one million, five hundred forty-seven thousand, two hundred fifty-two".