21340344 has 64 divisors (see below), whose sum is σ = 57283200. Its totient is φ = 6604416.

The previous prime is 21340339. The next prime is 21340351. The reversal of 21340344 is 44304312.

It is a self number, because there is not a number n which added to its sum of digits gives 21340344.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23727 + ... + 24609.

It is an arithmetic number, because the mean of its divisors is an integer number (895050).

Almost surely, 2^21340344 is an apocalyptic number.

21340344 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 21340344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28641600).

21340344 is an abundant number, since it is smaller than the sum of its proper divisors (35942856).

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

21340344 is a wasteful number, since it uses less digits than its factorization.

21340344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964 (or 960 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 21340344 is about 4619.5610181055. The cubic root of 21340344 is about 277.3748871927.

Adding to 21340344 its reverse (44304312), we get a palindrome (65644656).

The spelling of 21340344 in words is "twenty-one million, three hundred forty thousand, three hundred forty-four".