21290944 has 28 divisors (see below), whose sum is σ = 44475400. Its totient is φ = 10084608.

The previous prime is 21290933. The next prime is 21290999. The reversal of 21290944 is 44909212.

It is a happy number.

It is a super-2 number, since 2×21290944² = 906608592822272, which contains 22 as substring.

It is a congruent number.

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, 7539 + ... + 9970.

Almost surely, 2^21290944 is an apocalyptic number.

It is an amenable number.

21290944 is an abundant number, since it is smaller than the sum of its proper divisors (23184456).

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

21290944 is a wasteful number, since it uses less digits than its factorization.

21290944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17540 (or 17530 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21290944 is about 4614.2110918336. The cubic root of 21290944 is about 277.1606934252.

The spelling of 21290944 in words is "twenty-one million, two hundred ninety thousand, nine hundred forty-four".