21320323 has 2 divisors, whose sum is σ = 21320324. Its totient is φ = 21320322.

The previous prime is 21320317. The next prime is 21320401. The reversal of 21320323 is 32302312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21320323 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21320297 and 21320306.

It is not a weakly prime, because it can be changed into another prime (21350323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660161 + 10660162.

It is an arithmetic number, because the mean of its divisors is an integer number (10660162).

Almost surely, 2^21320323 is an apocalyptic number.

21320323 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320323 is an equidigital number, since it uses as much as digits as its factorization.

21320323 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 16.

The square root of 21320323 is about 4617.3935288212. The cubic root of 21320323 is about 277.2881178919.

Adding to 21320323 its reverse (32302312), we get a palindrome (53622635).

The spelling of 21320323 in words is "twenty-one million, three hundred twenty thousand, three hundred twenty-three".