21311113 has 2 divisors, whose sum is σ = 21311114. Its totient is φ = 21311112.

The previous prime is 21311111. The next prime is 21311117. The reversal of 21311113 is 31111312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16867449 + 4443664 = 4107^2 + 2108^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311113 - 2¹ = 21311111 is a prime.

Together with 21311111, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21311093 and 21311102.

It is not a weakly prime, because it can be changed into another prime (21311111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655556 + 10655557.

It is an arithmetic number, because the mean of its divisors is an integer number (10655557).

Almost surely, 2^21311113 is an apocalyptic number.

It is an amenable number.

21311113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311113 is an equidigital number, since it uses as much as digits as its factorization.

21311113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18, while the sum is 13.

The square root of 21311113 is about 4616.3961051885. The cubic root of 21311113 is about 277.2481842975.

Adding to 21311113 its reverse (31111312), we get a palindrome (52422425).

The spelling of 21311113 in words is "twenty-one million, three hundred eleven thousand, one hundred thirteen".