21228352 has 14 divisors (see below), whose sum is σ = 42125138. Its totient is φ = 10614144.

The previous prime is 21228341. The next prime is 21228371. The reversal of 21228352 is 25382212.

It can be written as a sum of positive squares in only one way, i.e., 21013056 + 215296 = 4584^2 + 464^2 .

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 165783 + ... + 165910.

Almost surely, 2^21228352 is an apocalyptic number.

It is an amenable number.

21228352 is a deficient number, since it is larger than the sum of its proper divisors (20896786).

21228352 is an equidigital number, since it uses as much as digits as its factorization.

21228352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331705 (or 331695 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21228352 is about 4607.4235750580. The cubic root of 21228352 is about 276.8888240002. Note that the first 4 decimals are identical.

The spelling of 21228352 in words is "twenty-one million, two hundred twenty-eight thousand, three hundred fifty-two".