21233812 has 6 divisors (see below), whose sum is σ = 37159178. Its totient is φ = 10616904.

The previous prime is 21233753. The next prime is 21233813. The reversal of 21233812 is 21833212.

It can be written as a sum of positive squares in only one way, i.e., 14243076 + 6990736 = 3774^2 + 2644^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2654223 + ... + 2654230.

Almost surely, 2^21233812 is an apocalyptic number.

It is an amenable number.

21233812 is a deficient number, since it is larger than the sum of its proper divisors (15925366).

21233812 is a wasteful number, since it uses less digits than its factorization.

21233812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5308457 (or 5308455 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

The square root of 21233812 is about 4608.0160589998. The cubic root of 21233812 is about 276.9125608621.

The spelling of 21233812 in words is "twenty-one million, two hundred thirty-three thousand, eight hundred twelve".