21121112113 has 2 divisors, whose sum is σ = 21121112114. Its totient is φ = 21121112112.

The previous prime is 21121112059. The next prime is 21121112147. The reversal of 21121112113 is 31121112112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19642863409 + 1478248704 = 140153^2 + 38448^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121112113 - 2⁹ = 21121111601 is a prime.

It is a super-2 number, since 2×21121112113² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121112183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560556056 + 10560556057.

It is an arithmetic number, because the mean of its divisors is an integer number (10560556057).

Almost surely, 2^21121112113 is an apocalyptic number.

It is an amenable number.

21121112113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121112113 is an equidigital number, since it uses as much as digits as its factorization.

21121112113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24, while the sum is 16.

Adding to 21121112113 its reverse (31121112112), we get a palindrome (52242224225).

Subtracting 21121112113 from its reverse (31121112112), we obtain a palindrome (9999999999).

The spelling of 21121112113 in words is "twenty-one billion, one hundred twenty-one million, one hundred twelve thousand, one hundred thirteen".