21633424 has 20 divisors (see below), whose sum is σ = 42140160. Its totient is φ = 10758560.

The previous prime is 21633421. The next prime is 21633427. The reversal of 21633424 is 42433612.

21633424 = 237² + 238² + ... + 427².

It is an interprime number because it is at equal distance from previous prime (21633421) and next prime (21633427).

It is not an unprimeable number, because it can be changed into a prime (21633421) 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, 484 + ... + 6595.

It is an arithmetic number, because the mean of its divisors is an integer number (2107008).

Almost surely, 2^21633424 is an apocalyptic number.

It is an amenable number.

21633424 is a deficient number, since it is larger than the sum of its proper divisors (20506736).

21633424 is a wasteful number, since it uses less digits than its factorization.

21633424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7278 (or 7272 counting only the distinct ones).

The product of its digits is 3456, while the sum is 25.

The square root of 21633424 is about 4651.1744753342. The cubic root of 21633424 is about 278.6389045650.

The spelling of 21633424 in words is "twenty-one million, six hundred thirty-three thousand, four hundred twenty-four".