21844745 has 32 divisors (see below), whose sum is σ = 30536352. Its totient is φ = 14856192.

The previous prime is 21844729. The next prime is 21844751. The reversal of 21844745 is 54744812.

It can be written as a sum of positive squares in 16 ways, for example, as 2930944 + 18913801 = 1712^2 + 4349^2 .

It is not a de Polignac number, because 21844745 - 2⁴ = 21844729 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58379 + ... + 58751.

It is an arithmetic number, because the mean of its divisors is an integer number (954261).

Almost surely, 2^21844745 is an apocalyptic number.

It is an amenable number.

21844745 is a deficient number, since it is larger than the sum of its proper divisors (8691607).

21844745 is a wasteful number, since it uses less digits than its factorization.

21844745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461.

The product of its digits is 35840, while the sum is 35.

The square root of 21844745 is about 4673.8362187822. The cubic root of 21844745 is about 279.5432391398.

The spelling of 21844745 in words is "twenty-one million, eight hundred forty-four thousand, seven hundred forty-five".