21853944 has 96 divisors (see below), whose sum is σ = 68365440. Its totient is φ = 6177600.

The previous prime is 21853927. The next prime is 21853961. The reversal of 21853944 is 44935812.

It is an interprime number because it is at equal distance from previous prime (21853927) and next prime (21853961).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21853899 and 21853908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 65859 + ... + 66189.

It is an arithmetic number, because the mean of its divisors is an integer number (712140).

Almost surely, 2^21853944 is an apocalyptic number.

21853944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21853944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34182720).

21853944 is an abundant number, since it is smaller than the sum of its proper divisors (46511496).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21853944 is a wasteful number, since it uses less digits than its factorization.

21853944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481 (or 474 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21853944 is about 4674.8202104466. The cubic root of 21853944 is about 279.5824729446.

The spelling of 21853944 in words is "twenty-one million, eight hundred fifty-three thousand, nine hundred forty-four".