21223944 has 80 divisors (see below), whose sum is σ = 67953600. Its totient is φ = 6062688.

The previous prime is 21223927. The next prime is 21223957. The reversal of 21223944 is 44932212.

It is a Harshad number since it is a multiple of its sum of digits (27).

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

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2197 + ... + 6875.

It is an arithmetic number, because the mean of its divisors is an integer number (849420).

Almost surely, 2^21223944 is an apocalyptic number.

21223944 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 21223944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33976800).

21223944 is an abundant number, since it is smaller than the sum of its proper divisors (46729656).

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

21223944 is a wasteful number, since it uses less digits than its factorization.

21223944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4704 (or 4691 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21223944 is about 4606.9451917730. The cubic root of 21223944 is about 276.8696576446.

The spelling of 21223944 in words is "twenty-one million, two hundred twenty-three thousand, nine hundred forty-four".