21320023511 has 2 divisors, whose sum is σ = 21320023512. Its totient is φ = 21320023510.

The previous prime is 21320023507. The next prime is 21320023513. The reversal of 21320023511 is 11532002312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21320023511 - 2² = 21320023507 is a prime.

Together with 21320023513, 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 (21320023513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660011755 + 10660011756.

It is an arithmetic number, because the mean of its divisors is an integer number (10660011756).

Almost surely, 2^21320023511 is an apocalyptic number.

21320023511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320023511 is an equidigital number, since it uses as much as digits as its factorization.

21320023511 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21320023511 its reverse (11532002312), we get a palindrome (32852025823).

The spelling of 21320023511 in words is "twenty-one billion, three hundred twenty million, twenty-three thousand, five hundred eleven".