21102311 has 2 divisors, whose sum is σ = 21102312. Its totient is φ = 21102310.

The previous prime is 21102307. The next prime is 21102313. The reversal of 21102311 is 11320112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21102311 - 2² = 21102307 is a prime.

It is a Sophie Germain prime.

Together with 21102313, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21102292 and 21102301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551155 + 10551156.

It is an arithmetic number, because the mean of its divisors is an integer number (10551156).

Almost surely, 2^21102311 is an apocalyptic number.

21102311 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102311 is an equidigital number, since it uses as much as digits as its factorization.

21102311 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21102311 is about 4593.7251768037. The cubic root of 21102311 is about 276.3397368903.

Adding to 21102311 its reverse (11320112), we get a palindrome (32422423).

The spelling of 21102311 in words is "twenty-one million, one hundred two thousand, three hundred eleven".