21444438 has 16 divisors (see below), whose sum is σ = 43217856. Its totient is φ = 7093320.

The previous prime is 21444433. The next prime is 21444457. The reversal of 21444438 is 83444412.

It is a super-2 number, since 2×21444438² = 919727842271688, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12856 + ... + 14427.

It is an arithmetic number, because the mean of its divisors is an integer number (2701116).

Almost surely, 2^21444438 is an apocalyptic number.

21444438 is an abundant number, since it is smaller than the sum of its proper divisors (21773418).

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

21444438 is a wasteful number, since it uses less digits than its factorization.

21444438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27419.

The product of its digits is 12288, while the sum is 30.

The square root of 21444438 is about 4630.8139673280. The cubic root of 21444438 is about 277.8251492661.

The spelling of 21444438 in words is "twenty-one million, four hundred forty-four thousand, four hundred thirty-eight".