21249252 has 36 divisors (see below), whose sum is σ = 56874636. Its totient is φ = 6666240.

The previous prime is 21249203. The next prime is 21249253. The reversal of 21249252 is 25294212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14561856 + 6687396 = 3816^2 + 2586^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (21249253) 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 11 ways as a sum of consecutive naturals, for example, 16749 + ... + 17972.

It is an arithmetic number, because the mean of its divisors is an integer number (1579851).

Almost surely, 2^21249252 is an apocalyptic number.

It is an amenable number.

21249252 is an abundant number, since it is smaller than the sum of its proper divisors (35625384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21249252 is a wasteful number, since it uses less digits than its factorization.

21249252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34748 (or 34743 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21249252 is about 4609.6910959412. The cubic root of 21249252 is about 276.9796628667.

The spelling of 21249252 in words is "twenty-one million, two hundred forty-nine thousand, two hundred fifty-two".