21669944 has 16 divisors (see below), whose sum is σ = 41238600. Its totient is φ = 10672992.

The previous prime is 21669943. The next prime is 21669959. The reversal of 21669944 is 44996612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21669943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19679 + ... + 20750.

Almost surely, 2^21669944 is an apocalyptic number.

It is an amenable number.

21669944 is a deficient number, since it is larger than the sum of its proper divisors (19568656).

21669944 is a wasteful number, since it uses less digits than its factorization.

21669944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40502 (or 40498 counting only the distinct ones).

The product of its digits is 93312, while the sum is 41.

The square root of 21669944 is about 4655.0987100168. The cubic root of 21669944 is about 278.7956091792.

The spelling of 21669944 in words is "twenty-one million, six hundred sixty-nine thousand, nine hundred forty-four".