21305323 has 6 divisors (see below), whose sum is σ = 23070444. Its totient is φ = 19666296.

The previous prime is 21305321. The next prime is 21305341. The reversal of 21305323 is 32350312.

It is not a de Polignac number, because 21305323 - 2¹ = 21305321 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21305323.

It is not an unprimeable number, because it can be changed into a prime (21305321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62865 + ... + 63202.

It is an arithmetic number, because the mean of its divisors is an integer number (3845074).

Almost surely, 2^21305323 is an apocalyptic number.

21305323 is a deficient number, since it is larger than the sum of its proper divisors (1765121).

21305323 is a wasteful number, since it uses less digits than its factorization.

21305323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126093 (or 126080 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 19.

The square root of 21305323 is about 4615.7689500234. The cubic root of 21305323 is about 277.2230735742.

Adding to 21305323 its reverse (32350312), we get a palindrome (53655635).

The spelling of 21305323 in words is "twenty-one million, three hundred five thousand, three hundred twenty-three".