21383644 has 12 divisors (see below), whose sum is σ = 37652104. Its totient is φ = 10625904.

The previous prime is 21383633. The next prime is 21383651. The reversal of 21383644 is 44638312.

It is a super-3 number, since 3×21383644³ (a number of 23 digits) contains 333 as substring.

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, 15747 + ... + 17050.

Almost surely, 2^21383644 is an apocalyptic number.

It is an amenable number.

21383644 is a deficient number, since it is larger than the sum of its proper divisors (16268460).

21383644 is a wasteful number, since it uses less digits than its factorization.

21383644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32964 (or 32962 counting only the distinct ones).

The product of its digits is 13824, while the sum is 31.

The square root of 21383644 is about 4624.2452357114. The cubic root of 21383644 is about 277.5623602514.

The spelling of 21383644 in words is "twenty-one million, three hundred eighty-three thousand, six hundred forty-four".