21233628 has 72 divisors (see below), whose sum is σ = 58858800. Its totient is φ = 6414336.

The previous prime is 21233627. The next prime is 21233633. The reversal of 21233628 is 82633212.

21233628 is a `hidden beast` number, since 2 + 1 + 2 + 33 + 628 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27228 + ... + 27996.

Almost surely, 2^21233628 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 21233628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29429400).

21233628 is an abundant number, since it is smaller than the sum of its proper divisors (37625172).

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

21233628 is a wasteful number, since it uses less digits than its factorization.

21233628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851 (or 846 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21233628 is about 4607.9960937483. The cubic root of 21233628 is about 276.9117610048.

The spelling of 21233628 in words is "twenty-one million, two hundred thirty-three thousand, six hundred twenty-eight".