21323311 has 2 divisors, whose sum is σ = 21323312. Its totient is φ = 21323310.

The previous prime is 21323297. The next prime is 21323371. The reversal of 21323311 is 11332312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21323311 - 2⁹ = 21322799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21323371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661655 + 10661656.

It is an arithmetic number, because the mean of its divisors is an integer number (10661656).

Almost surely, 2^21323311 is an apocalyptic number.

21323311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323311 is an equidigital number, since it uses as much as digits as its factorization.

21323311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 16.

The square root of 21323311 is about 4617.7170766516. The cubic root of 21323311 is about 277.3010710758.

Adding to 21323311 its reverse (11332312), we get a palindrome (32655623).

Subtracting from 21323311 its reverse (11332312), we obtain a palindrome (9990999).

The spelling of 21323311 in words is "twenty-one million, three hundred twenty-three thousand, three hundred eleven".