21442344 has 128 divisors (see below), whose sum is σ = 68705280. Its totient is φ = 5414400.

The previous prime is 21442331. The next prime is 21442349. The reversal of 21442344 is 44324412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

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 (21442349) 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, 75627 + ... + 75909.

It is an arithmetic number, because the mean of its divisors is an integer number (536760).

Almost surely, 2^21442344 is an apocalyptic number.

21442344 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 21442344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34352640).

21442344 is an abundant number, since it is smaller than the sum of its proper divisors (47262936).

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

21442344 is a wasteful number, since it uses less digits than its factorization.

21442344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351 (or 347 counting only the distinct ones).

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

The square root of 21442344 is about 4630.5878676470. The cubic root of 21442344 is about 277.8161059764.

Adding to 21442344 its reverse (44324412), we get a palindrome (65766756).

The spelling of 21442344 in words is "twenty-one million, four hundred forty-two thousand, three hundred forty-four".