21311320333 has 2 divisors, whose sum is σ = 21311320334. Its totient is φ = 21311320332.

The previous prime is 21311320297. The next prime is 21311320351. The reversal of 21311320333 is 33302311312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20594259049 + 717061284 = 143507^2 + 26778^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311320333 - 2¹⁷ = 21311189261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311320633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655660166 + 10655660167.

It is an arithmetic number, because the mean of its divisors is an integer number (10655660167).

Almost surely, 2^21311320333 is an apocalyptic number.

It is an amenable number.

21311320333 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311320333 is an equidigital number, since it uses as much as digits as its factorization.

21311320333 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 22.

Adding to 21311320333 its reverse (33302311312), we get a palindrome (54613631645).

The spelling of 21311320333 in words is "twenty-one billion, three hundred eleven million, three hundred twenty thousand, three hundred thirty-three".