21093228 has 54 divisors (see below), whose sum is σ = 57752604. Its totient is φ = 6488352.

The previous prime is 21093217. The next prime is 21093239. The reversal of 21093228 is 82239012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21093217) and next prime (21093239).

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 in 17 ways as a sum of consecutive naturals, for example, 4351 + ... + 7817.

Almost surely, 2^21093228 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21093228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28876302).

21093228 is an abundant number, since it is smaller than the sum of its proper divisors (36659376).

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

21093228 is a wasteful number, since it uses less digits than its factorization.

21093228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3503 (or 3485 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21093228 is about 4592.7364392048. The cubic root of 21093228 is about 276.3000831917.

It can be divided in two parts, 21093 and 228, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 21093228 in words is "twenty-one million, ninety-three thousand, two hundred twenty-eight".