21044388 has 24 divisors (see below), whose sum is σ = 49180320. Its totient is φ = 7003840.

The previous prime is 21044383. The next prime is 21044389. The reversal of 21044388 is 88344012.

It is not an unprimeable number, because it can be changed into a prime (21044383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11368 + ... + 13088.

It is an arithmetic number, because the mean of its divisors is an integer number (2049180).

Almost surely, 2^21044388 is an apocalyptic number.

It is an amenable number.

21044388 is an abundant number, since it is smaller than the sum of its proper divisors (28135932).

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

21044388 is a wasteful number, since it uses less digits than its factorization.

21044388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2747 (or 2745 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 21044388 is about 4587.4162662658. The cubic root of 21044388 is about 276.0866667548.

The spelling of 21044388 in words is "twenty-one million, forty-four thousand, three hundred eighty-eight".