21330311 has 2 divisors, whose sum is σ = 21330312. Its totient is φ = 21330310.

The previous prime is 21330299. The next prime is 21330313. The reversal of 21330311 is 11303312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21330311 - 2¹⁸ = 21068167 is a prime.

It is a super-3 number, since 3×21330311³ (a number of 23 digits) contains 333 as substring.

Together with 21330313, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21330313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665155 + 10665156.

It is an arithmetic number, because the mean of its divisors is an integer number (10665156).

Almost surely, 2^21330311 is an apocalyptic number.

21330311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21330311 is an equidigital number, since it uses as much as digits as its factorization.

21330311 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 21330311 is about 4618.4749647476. The cubic root of 21330311 is about 277.3314118161.

Adding to 21330311 its reverse (11303312), we get a palindrome (32633623).

The spelling of 21330311 in words is "twenty-one million, three hundred thirty thousand, three hundred eleven".