21111065513 has 2 divisors, whose sum is σ = 21111065514. Its totient is φ = 21111065512.

The previous prime is 21111065497. The next prime is 21111065519. The reversal of 21111065513 is 31556011112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19399754089 + 1711311424 = 139283^2 + 41368^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111065513 - 2⁴ = 21111065497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111065519) 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, 10555532756 + 10555532757.

It is an arithmetic number, because the mean of its divisors is an integer number (10555532757).

Almost surely, 2^21111065513 is an apocalyptic number.

It is an amenable number.

21111065513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111065513 is an equidigital number, since it uses as much as digits as its factorization.

21111065513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 26.

Adding to 21111065513 its reverse (31556011112), we get a palindrome (52667076625).

The spelling of 21111065513 in words is "twenty-one billion, one hundred eleven million, sixty-five thousand, five hundred thirteen".