21427228 has 12 divisors (see below), whose sum is σ = 37531480. Its totient is φ = 10703952.

The previous prime is 21427223. The next prime is 21427247. The reversal of 21427228 is 82272412.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21427196 and 21427205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21427223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5338 + ... + 8446.

Almost surely, 2^21427228 is an apocalyptic number.

It is an amenable number.

21427228 is a deficient number, since it is larger than the sum of its proper divisors (16104252).

21427228 is a wasteful number, since it uses less digits than its factorization.

21427228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4836 (or 4834 counting only the distinct ones).

The product of its digits is 3584, while the sum is 28.

The square root of 21427228 is about 4628.9553897181. The cubic root of 21427228 is about 277.7508075266.

The spelling of 21427228 in words is "twenty-one million, four hundred twenty-seven thousand, two hundred twenty-eight".