21990983 has 4 divisors (see below), whose sum is σ = 25132560. Its totient is φ = 18849408.

The previous prime is 21990977. The next prime is 21990989. The reversal of 21990983 is 38909912.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21990977) and next prime (21990989).

It is a cyclic number.

It is not a de Polignac number, because 21990983 - 2¹⁴ = 21974599 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21990983.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21990989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1570778 + ... + 1570791.

It is an arithmetic number, because the mean of its divisors is an integer number (6283140).

Almost surely, 2^21990983 is an apocalyptic number.

21990983 is a deficient number, since it is larger than the sum of its proper divisors (3141577).

21990983 is an equidigital number, since it uses as much as digits as its factorization.

21990983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3141576.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 21990983 is about 4689.4544458817. The cubic root of 21990983 is about 280.1656460333.

The spelling of 21990983 in words is "twenty-one million, nine hundred ninety thousand, nine hundred eighty-three".