21444234 has 64 divisors (see below), whose sum is σ = 51978240. Its totient is φ = 5765760.

The previous prime is 21444233. The next prime is 21444239. The reversal of 21444234 is 43244412.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21444233) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 76174 + ... + 76454.

It is an arithmetic number, because the mean of its divisors is an integer number (812160).

Almost surely, 2^21444234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21444234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25989120).

21444234 is an abundant number, since it is smaller than the sum of its proper divisors (30534006).

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

21444234 is a wasteful number, since it uses less digits than its factorization.

21444234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395.

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

The square root of 21444234 is about 4630.7919409103. The cubic root of 21444234 is about 277.8242682838.

Adding to 21444234 its reverse (43244412), we get a palindrome (64688646).

The spelling of 21444234 in words is "twenty-one million, four hundred forty-four thousand, two hundred thirty-four".