21228252 has 24 divisors (see below), whose sum is σ = 49635600. Its totient is φ = 7061376.

The previous prime is 21228247. The next prime is 21228289. The reversal of 21228252 is 25282212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5274 + ... + 8382.

It is an arithmetic number, because the mean of its divisors is an integer number (2068150).

Almost surely, 2^21228252 is an apocalyptic number.

It is an amenable number.

21228252 is an abundant number, since it is smaller than the sum of its proper divisors (28407348).

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

21228252 is a wasteful number, since it uses less digits than its factorization.

21228252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3685 (or 3683 counting only the distinct ones).

The product of its digits is 1280, while the sum is 24.

The square root of 21228252 is about 4607.4127229932. The cubic root of 21228252 is about 276.8883892212. Note that the first 3 decimals are identical.

The spelling of 21228252 in words is "twenty-one million, two hundred twenty-eight thousand, two hundred fifty-two".