21210244 has 12 divisors (see below), whose sum is σ = 40492368. Its totient is φ = 9641000.

The previous prime is 21210227. The next prime is 21210269. The reversal of 21210244 is 44201212.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 240982 + ... + 241069.

It is an arithmetic number, because the mean of its divisors is an integer number (3374364).

Almost surely, 2^21210244 is an apocalyptic number.

It is an amenable number.

21210244 is a deficient number, since it is larger than the sum of its proper divisors (19282124).

21210244 is a wasteful number, since it uses less digits than its factorization.

21210244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482066 (or 482064 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21210244 is about 4605.4580662514. The cubic root of 21210244 is about 276.8100719435.

Adding to 21210244 its reverse (44201212), we get a palindrome (65411456).

The spelling of 21210244 in words is "twenty-one million, two hundred ten thousand, two hundred forty-four".