21344399 has 8 divisors (see below), whose sum is σ = 22185600. Its totient is φ = 20512800.

The previous prime is 21344369. The next prime is 21344417. The reversal of 21344399 is 99344312.

It is a Cunningham number, because it is equal to 4620²-1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21344399 - 2²⁴ = 4567183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21344339) 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, 2309 + ... + 6929.

It is an arithmetic number, because the mean of its divisors is an integer number (2773200).

Almost surely, 2^21344399 is an apocalyptic number.

21344399 is a deficient number, since it is larger than the sum of its proper divisors (841201).

21344399 is a wasteful number, since it uses less digits than its factorization.

21344399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4801.

The product of its digits is 23328, while the sum is 35.

The square root of 21344399 is about 4619.9998917749. Note that the first 3 decimals coincide. The cubic root of 21344399 is about 277.3924546061.

The spelling of 21344399 in words is "twenty-one million, three hundred forty-four thousand, three hundred ninety-nine".