21342144 has 56 divisors (see below), whose sum is σ = 58430160. Its totient is φ = 6866944.

The previous prime is 21342143. The next prime is 21342161. The reversal of 21342144 is 44124312.

It is a super-2 number, since 2×21342144² = 910974221033472, which contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21342144.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21342143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3652 + ... + 7484.

Almost surely, 2^21342144 is an apocalyptic number.

21342144 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 21342144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29215080).

21342144 is an abundant number, since it is smaller than the sum of its proper divisors (37088016).

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

21342144 is a wasteful number, since it uses less digits than its factorization.

21342144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3877 (or 3867 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 21342144 is about 4619.7558377040. The cubic root of 21342144 is about 277.3826855794.

Adding to 21342144 its reverse (44124312), we get a palindrome (65466456).

It can be divided in two parts, 2134 and 2144, that added together give a triangular number (4278 = T₉₂).

The spelling of 21342144 in words is "twenty-one million, three hundred forty-two thousand, one hundred forty-four".