21304344 has 16 divisors (see below), whose sum is σ = 53260920. Its totient is φ = 7101440.

The previous prime is 21304333. The next prime is 21304351. The reversal of 21304344 is 44340312.

It is a self number, because there is not a number n which added to its sum of digits gives 21304344.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 443817 + ... + 443864.

Almost surely, 2^21304344 is an apocalyptic number.

21304344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21304344 is an abundant number, since it is smaller than the sum of its proper divisors (31956576).

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

21304344 is a wasteful number, since it uses less digits than its factorization.

21304344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 887690 (or 887686 counting only the distinct ones).

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

The square root of 21304344 is about 4615.6628993028. The cubic root of 21304344 is about 277.2188272872.

Adding to 21304344 its reverse (44340312), we get a palindrome (65644656).

The spelling of 21304344 in words is "twenty-one million, three hundred four thousand, three hundred forty-four".