21791944 has 16 divisors (see below), whose sum is σ = 40967820. Its totient is φ = 10867200.

The previous prime is 21791921. The next prime is 21791969. The reversal of 21791944 is 44919712.

It can be written as a sum of positive squares in 2 ways, for example, as 21511044 + 280900 = 4638^2 + 530^2 .

It is a plaindrome in base 11.

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, 189 + ... + 6604.

Almost surely, 2^21791944 is an apocalyptic number.

It is an amenable number.

21791944 is a deficient number, since it is larger than the sum of its proper divisors (19175876).

21791944 is a wasteful number, since it uses less digits than its factorization.

21791944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7200 (or 7196 counting only the distinct ones).

The product of its digits is 18144, while the sum is 37.

The square root of 21791944 is about 4668.1842294408. The cubic root of 21791944 is about 279.3178291561.

The spelling of 21791944 in words is "twenty-one million, seven hundred ninety-one thousand, nine hundred forty-four".