21884979 has 16 divisors (see below), whose sum is σ = 31433600. Its totient is φ = 13499136.

The previous prime is 21884957. The next prime is 21884981. The reversal of 21884979 is 97948812.

It is not a de Polignac number, because 21884979 - 2⁷ = 21884851 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21880979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2014 + ... + 6915.

It is an arithmetic number, because the mean of its divisors is an integer number (1964600).

Almost surely, 2^21884979 is an apocalyptic number.

21884979 is a deficient number, since it is larger than the sum of its proper divisors (9548621).

21884979 is a wasteful number, since it uses less digits than its factorization.

21884979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8994.

The product of its digits is 290304, while the sum is 48.

The square root of 21884979 is about 4678.1384118044. The cubic root of 21884979 is about 279.7147562817.

The spelling of 21884979 in words is "twenty-one million, eight hundred eighty-four thousand, nine hundred seventy-nine".