21633244 has 6 divisors (see below), whose sum is σ = 37858184. Its totient is φ = 10816620.

The previous prime is 21633239. The next prime is 21633247. The reversal of 21633244 is 44233612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21633247) by changing a digit.

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 as a sum of consecutive naturals, namely, 2704152 + ... + 2704159.

Almost surely, 2^21633244 is an apocalyptic number.

It is an amenable number.

21633244 is a deficient number, since it is larger than the sum of its proper divisors (16224940).

21633244 is a wasteful number, since it uses less digits than its factorization.

21633244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5408315 (or 5408313 counting only the distinct ones).

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

The square root of 21633244 is about 4651.1551253425. The cubic root of 21633244 is about 278.6381317617.

Adding to 21633244 its reverse (44233612), we get a palindrome (65866856).

The spelling of 21633244 in words is "twenty-one million, six hundred thirty-three thousand, two hundred forty-four".