21242812 has 24 divisors (see below), whose sum is σ = 38646272. Its totient is φ = 10206000.

The previous prime is 21242807. The next prime is 21242821. The reversal of 21242812 is 21824212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19687 + ... + 20737.

Almost surely, 2^21242812 is an apocalyptic number.

It is an amenable number.

21242812 is a deficient number, since it is larger than the sum of its proper divisors (17403460).

21242812 is a wasteful number, since it uses less digits than its factorization.

21242812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1249 (or 1247 counting only the distinct ones).

The product of its digits is 512, while the sum is 22.

The square root of 21242812 is about 4608.9925146392. The cubic root of 21242812 is about 276.9516786776.

The spelling of 21242812 in words is "twenty-one million, two hundred forty-two thousand, eight hundred twelve".