21809983 has 8 divisors (see below), whose sum is σ = 24123008. Its totient is φ = 19587744.

The previous prime is 21809971. The next prime is 21810007. The reversal of 21809983 is 38990812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21809983 - 2⁵ = 21809951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21809903) 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, 22191 + ... + 23152.

It is an arithmetic number, because the mean of its divisors is an integer number (3015376).

Almost surely, 2^21809983 is an apocalyptic number.

21809983 is a deficient number, since it is larger than the sum of its proper divisors (2313025).

21809983 is a wasteful number, since it uses less digits than its factorization.

21809983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45393.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 21809983 is about 4670.1159514513. The cubic root of 21809983 is about 279.3948794133.

The spelling of 21809983 in words is "twenty-one million, eight hundred nine thousand, nine hundred eighty-three".