21234444 has 120 divisors (see below), whose sum is σ = 63997248. Its totient is φ = 5433120.

The previous prime is 21234443. The next prime is 21234461. The reversal of 21234444 is 44443212.

It is a happy number.

It is a super-2 number, since 2×21234444² = 901803223978272, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21234443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 316899 + ... + 316965.

Almost surely, 2^21234444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21234444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31998624).

21234444 is an abundant number, since it is smaller than the sum of its proper divisors (42762804).

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

21234444 is a wasteful number, since it uses less digits than its factorization.

21234444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 90 counting only the distinct ones).

The product of its digits is 3072, while the sum is 24.

The square root of 21234444 is about 4608.0846346394. The cubic root of 21234444 is about 276.9153081629.

Adding to 21234444 its reverse (44443212), we get a palindrome (65677656).

The spelling of 21234444 in words is "twenty-one million, two hundred thirty-four thousand, four hundred forty-four".