21105244 has 24 divisors (see below), whose sum is σ = 38591280. Its totient is φ = 10089216.

The previous prime is 21105239. The next prime is 21105307. The reversal of 21105244 is 44250112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7524 + ... + 9940.

It is an arithmetic number, because the mean of its divisors is an integer number (1607970).

Almost surely, 2^21105244 is an apocalyptic number.

It is an amenable number.

21105244 is a deficient number, since it is larger than the sum of its proper divisors (17486036).

21105244 is a wasteful number, since it uses less digits than its factorization.

21105244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2517 (or 2515 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21105244 is about 4594.0444055320. The cubic root of 21105244 is about 276.3525390727.

Adding to 21105244 its reverse (44250112), we get a palindrome (65355356).

The spelling of 21105244 in words is "twenty-one million, one hundred five thousand, two hundred forty-four".