21859983 has 8 divisors (see below), whose sum is σ = 32385200. Its totient is φ = 14573304.

The previous prime is 21859979. The next prime is 21859987. The reversal of 21859983 is 38995812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21859979) and next prime (21859987).

It is not a de Polignac number, because 21859983 - 2² = 21859979 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859987) 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, 404788 + ... + 404841.

It is an arithmetic number, because the mean of its divisors is an integer number (4048150).

Almost surely, 2^21859983 is an apocalyptic number.

21859983 is a deficient number, since it is larger than the sum of its proper divisors (10525217).

21859983 is an equidigital number, since it uses as much as digits as its factorization.

21859983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 809638 (or 809632 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 21859983 is about 4675.4660730242. The cubic root of 21859983 is about 279.6082233393.

The spelling of 21859983 in words is "twenty-one million, eight hundred fifty-nine thousand, nine hundred eighty-three".