21916944 has 120 divisors (see below), whose sum is σ = 74280960. Its totient is φ = 5889024.

The previous prime is 21916901. The next prime is 21916967. The reversal of 21916944 is 44961912.

It is a happy number.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21916899 and 21916908.

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 23 ways as a sum of consecutive naturals, for example, 16497 + ... + 17775.

It is an arithmetic number, because the mean of its divisors is an integer number (619008).

Almost surely, 2^21916944 is an apocalyptic number.

21916944 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 21916944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37140480).

21916944 is an abundant number, since it is smaller than the sum of its proper divisors (52364016).

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

21916944 is a wasteful number, since it uses less digits than its factorization.

21916944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1317 (or 1308 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21916944 is about 4681.5535882867. The cubic root of 21916944 is about 279.8508729705.

The spelling of 21916944 in words is "twenty-one million, nine hundred sixteen thousand, nine hundred forty-four".