21115011013 has 2 divisors, whose sum is σ = 21115011014. Its totient is φ = 21115011012.

The previous prime is 21115010963. The next prime is 21115011031. The reversal of 21115011013 is 31011051112.

It is a happy number.

Together with next prime (21115011031) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11911103044 + 9203907969 = 109138^2 + 95937^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21115011013 is a prime.

It is a super-2 number, since 2×21115011013² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115011053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557505506 + 10557505507.

It is an arithmetic number, because the mean of its divisors is an integer number (10557505507).

Almost surely, 2^21115011013 is an apocalyptic number.

It is an amenable number.

21115011013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115011013 is an equidigital number, since it uses as much as digits as its factorization.

21115011013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30, while the sum is 16.

Adding to 21115011013 its reverse (31011051112), we get a palindrome (52126062125).

The spelling of 21115011013 in words is "twenty-one billion, one hundred fifteen million, eleven thousand, thirteen".