21937643 has 12 divisors (see below), whose sum is σ = 27483120. Its totient is φ = 17356752.

The previous prime is 21937639. The next prime is 21937679. The reversal of 21937643 is 34673912.

It is not a de Polignac number, because 21937643 - 2² = 21937639 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21937843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16583 + ... + 17856.

It is an arithmetic number, because the mean of its divisors is an integer number (2290260).

Almost surely, 2^21937643 is an apocalyptic number.

21937643 is a deficient number, since it is larger than the sum of its proper divisors (5545477).

21937643 is a wasteful number, since it uses less digits than its factorization.

21937643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34466 (or 34459 counting only the distinct ones).

The product of its digits is 27216, while the sum is 35.

The square root of 21937643 is about 4683.7637643246. The cubic root of 21937643 is about 279.9389450210.

The spelling of 21937643 in words is "twenty-one million, nine hundred thirty-seven thousand, six hundred forty-three".