21228236 has 6 divisors (see below), whose sum is σ = 37149420. Its totient is φ = 10614116.

The previous prime is 21228227. The next prime is 21228247. The reversal of 21228236 is 63282212.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2653526 + ... + 2653533.

It is an arithmetic number, because the mean of its divisors is an integer number (6191570).

Almost surely, 2^21228236 is an apocalyptic number.

It is an amenable number.

21228236 is a deficient number, since it is larger than the sum of its proper divisors (15921184).

21228236 is a wasteful number, since it uses less digits than its factorization.

21228236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5307063 (or 5307061 counting only the distinct ones).

The product of its digits is 2304, while the sum is 26.

The square root of 21228236 is about 4607.4109866605. The cubic root of 21228236 is about 276.8883196564. Note that the first 3 decimals are identical.

The spelling of 21228236 in words is "twenty-one million, two hundred twenty-eight thousand, two hundred thirty-six".