21111312073 has 2 divisors, whose sum is σ = 21111312074. Its totient is φ = 21111312072.

The previous prime is 21111312043. The next prime is 21111312127. The reversal of 21111312073 is 37021311112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19849428544 + 1261883529 = 140888^2 + 35523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111312073 - 2²⁹ = 20574441161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111312043) 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, 10555656036 + 10555656037.

It is an arithmetic number, because the mean of its divisors is an integer number (10555656037).

Almost surely, 2^21111312073 is an apocalyptic number.

It is an amenable number.

21111312073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111312073 is an equidigital number, since it uses as much as digits as its factorization.

21111312073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 252, while the sum is 22.

Adding to 21111312073 its reverse (37021311112), we get a palindrome (58132623185).

The spelling of 21111312073 in words is "twenty-one billion, one hundred eleven million, three hundred twelve thousand, seventy-three".