21844989 has 24 divisors (see below), whose sum is σ = 33002112. Its totient is φ = 13910400.

The previous prime is 21844969. The next prime is 21844993. The reversal of 21844989 is 98944812.

It is not a de Polignac number, because 21844989 - 2¹⁵ = 21812221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21844919) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17589 + ... + 18789.

It is an arithmetic number, because the mean of its divisors is an integer number (1375088).

Almost surely, 2^21844989 is an apocalyptic number.

It is an amenable number.

21844989 is a deficient number, since it is larger than the sum of its proper divisors (11157123).

21844989 is a wasteful number, since it uses less digits than its factorization.

21844989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1297 (or 1294 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 21844989 is about 4673.8623214639. The cubic root of 21844989 is about 279.5442799439.

The spelling of 21844989 in words is "twenty-one million, eight hundred forty-four thousand, nine hundred eighty-nine".