21303321 has 8 divisors (see below), whose sum is σ = 30589440. Its totient is φ = 13109712.

The previous prime is 21303319. The next prime is 21303341. The reversal of 21303321 is 12330312.

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

It is not a de Polignac number, because 21303321 - 2¹ = 21303319 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21303321.

It is not an unprimeable number, because it can be changed into a prime (21303301) 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, 273081 + ... + 273158.

It is an arithmetic number, because the mean of its divisors is an integer number (3823680).

Almost surely, 2^21303321 is an apocalyptic number.

It is an amenable number.

21303321 is a deficient number, since it is larger than the sum of its proper divisors (9286119).

21303321 is a wasteful number, since it uses less digits than its factorization.

21303321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546255.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21303321 is about 4615.5520796542. The cubic root of 21303321 is about 277.2143900169.

Adding to 21303321 its reverse (12330312), we get a palindrome (33633633).

The spelling of 21303321 in words is "twenty-one million, three hundred three thousand, three hundred twenty-one".