21118944 has 96 divisors (see below), whose sum is σ = 69140736. Its totient is φ = 5483520.

The previous prime is 21118927. The next prime is 21118949. The reversal of 21118944 is 44981112.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21118949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5964 + ... + 8820.

It is an arithmetic number, because the mean of its divisors is an integer number (720216).

Almost surely, 2^21118944 is an apocalyptic number.

21118944 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 21118944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34570368).

21118944 is an abundant number, since it is smaller than the sum of its proper divisors (48021792).

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

21118944 is a wasteful number, since it uses less digits than its factorization.

21118944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2888 (or 2880 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 21118944 is about 4595.5352245413. The cubic root of 21118944 is about 276.4123221748.

The spelling of 21118944 in words is "twenty-one million, one hundred eighteen thousand, nine hundred forty-four".