21844871 has 4 divisors (see below), whose sum is σ = 22794672. Its totient is φ = 20895072.

The previous prime is 21844831. The next prime is 21844873. The reversal of 21844871 is 17844812.

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

It is a cyclic number.

It is not a de Polignac number, because 21844871 - 2⁶ = 21844807 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 (21844873) 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 3 ways as a sum of consecutive naturals, for example, 474866 + ... + 474911.

It is an arithmetic number, because the mean of its divisors is an integer number (5698668).

Almost surely, 2^21844871 is an apocalyptic number.

21844871 is a deficient number, since it is larger than the sum of its proper divisors (949801).

21844871 is an equidigital number, since it uses as much as digits as its factorization.

21844871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 949800.

The product of its digits is 14336, while the sum is 35.

The square root of 21844871 is about 4673.8496980541. The cubic root of 21844871 is about 279.5437766052.

The spelling of 21844871 in words is "twenty-one million, eight hundred forty-four thousand, eight hundred seventy-one".