21372244 has 12 divisors (see below), whose sum is σ = 39027744. Its totient is φ = 10221464.

The previous prime is 21372233. The next prime is 21372269. The reversal of 21372244 is 44227312.

It is a happy number.

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 3 ways as a sum of consecutive naturals, for example, 116062 + ... + 116245.

It is an arithmetic number, because the mean of its divisors is an integer number (3252312).

Almost surely, 2^21372244 is an apocalyptic number.

It is an amenable number.

21372244 is a deficient number, since it is larger than the sum of its proper divisors (17655500).

21372244 is a wasteful number, since it uses less digits than its factorization.

21372244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232334 (or 232332 counting only the distinct ones).

The product of its digits is 2688, while the sum is 25.

The square root of 21372244 is about 4623.0124377942. The cubic root of 21372244 is about 277.5130270107.

Adding to 21372244 its reverse (44227312), we get a palindrome (65599556).

The spelling of 21372244 in words is "twenty-one million, three hundred seventy-two thousand, two hundred forty-four".