21853844 has 6 divisors (see below), whose sum is σ = 38244234. Its totient is φ = 10926920.

The previous prime is 21853831. The next prime is 21853889. The reversal of 21853844 is 44835812.

It can be written as a sum of positive squares in only one way, i.e., 21808900 + 44944 = 4670^2 + 212^2 .

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2731727 + ... + 2731734.

It is an arithmetic number, because the mean of its divisors is an integer number (6374039).

Almost surely, 2^21853844 is an apocalyptic number.

It is an amenable number.

21853844 is a deficient number, since it is larger than the sum of its proper divisors (16390390).

21853844 is a wasteful number, since it uses less digits than its factorization.

21853844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5463465 (or 5463463 counting only the distinct ones).

The product of its digits is 30720, while the sum is 35.

The square root of 21853844 is about 4674.8095148359. The cubic root of 21853844 is about 279.5820465030.

The spelling of 21853844 in words is "twenty-one million, eight hundred fifty-three thousand, eight hundred forty-four".