21389244 has 24 divisors (see below), whose sum is σ = 50050560. Its totient is φ = 7109424.

The previous prime is 21389239. The next prime is 21389257. The reversal of 21389244 is 44298312.

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, 2197 + ... + 6899.

It is an arithmetic number, because the mean of its divisors is an integer number (2085440).

Almost surely, 2^21389244 is an apocalyptic number.

It is an amenable number.

21389244 is an abundant number, since it is smaller than the sum of its proper divisors (28661316).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21389244 is a wasteful number, since it uses less digits than its factorization.

21389244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5089 (or 5087 counting only the distinct ones).

The product of its digits is 13824, while the sum is 33.

The square root of 21389244 is about 4624.8507002929. The cubic root of 21389244 is about 277.5865877023.

The spelling of 21389244 in words is "twenty-one million, three hundred eighty-nine thousand, two hundred forty-four".