21021944 has 16 divisors (see below), whose sum is σ = 39521400. Its totient is φ = 10482912.

The previous prime is 21021899. The next prime is 21021953. The reversal of 21021944 is 44912012.

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, 134 + ... + 6485.

Almost surely, 2^21021944 is an apocalyptic number.

It is an amenable number.

21021944 is a deficient number, since it is larger than the sum of its proper divisors (18499456).

21021944 is a wasteful number, since it uses less digits than its factorization.

21021944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7022 (or 7018 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21021944 is about 4584.9693564952. The cubic root of 21021944 is about 275.9884823311.

Adding to 21021944 its reverse (44912012), we get a palindrome (65933956).

The spelling of 21021944 in words is "twenty-one million, twenty-one thousand, nine hundred forty-four".