21252436 has 12 divisors (see below), whose sum is σ = 37254112. Its totient is φ = 10608408.

The previous prime is 21252433. The next prime is 21252443. The reversal of 21252436 is 63425212.

It is a self number, because there is not a number n which added to its sum of digits gives 21252436.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1560 + ... + 6703.

Almost surely, 2^21252436 is an apocalyptic number.

It is an amenable number.

21252436 is a deficient number, since it is larger than the sum of its proper divisors (16001676).

21252436 is a wasteful number, since it uses less digits than its factorization.

21252436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8910 (or 8908 counting only the distinct ones).

The product of its digits is 2880, while the sum is 25.

The square root of 21252436 is about 4610.0364423722. The cubic root of 21252436 is about 276.9934964392.

Adding to 21252436 its reverse (63425212), we get a palindrome (84677648).

The spelling of 21252436 in words is "twenty-one million, two hundred fifty-two thousand, four hundred thirty-six".