21913844 has 24 divisors (see below), whose sum is σ = 40134528. Its totient is φ = 10458560.

The previous prime is 21913831. The next prime is 21913849. The reversal of 21913844 is 44831912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21913844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21913849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6287 + ... + 9129.

It is an arithmetic number, because the mean of its divisors is an integer number (1672272).

Almost surely, 2^21913844 is an apocalyptic number.

It is an amenable number.

21913844 is a deficient number, since it is larger than the sum of its proper divisors (18220684).

21913844 is a wasteful number, since it uses less digits than its factorization.

21913844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2935 (or 2933 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 21913844 is about 4681.2224899058. Note that the first 3 decimals coincide. The cubic root of 21913844 is about 279.8376780255.

The spelling of 21913844 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred forty-four".