21535252 has 12 divisors (see below), whose sum is σ = 37879380. Its totient is φ = 10712576.

The previous prime is 21535247. The next prime is 21535253. The reversal of 21535252 is 25253512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17023876 + 4511376 = 4126^2 + 2124^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21535253) 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, 12877 + ... + 14452.

It is an arithmetic number, because the mean of its divisors is an integer number (3156615).

Almost surely, 2^21535252 is an apocalyptic number.

It is an amenable number.

21535252 is a deficient number, since it is larger than the sum of its proper divisors (16344128).

21535252 is a wasteful number, since it uses less digits than its factorization.

21535252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27530 (or 27528 counting only the distinct ones).

The product of its digits is 3000, while the sum is 25.

The square root of 21535252 is about 4640.6090117570. The cubic root of 21535252 is about 278.2167796581.

Adding to 21535252 its reverse (25253512), we get a palindrome (46788764).

The spelling of 21535252 in words is "twenty-one million, five hundred thirty-five thousand, two hundred fifty-two".