21103212073 has 2 divisors, whose sum is σ = 21103212074. Its totient is φ = 21103212072.

The previous prime is 21103212041. The next prime is 21103212077. The reversal of 21103212073 is 37021230112.

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., 18248767744 + 2854444329 = 135088^2 + 53427^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103212073 - 2⁵ = 21103212041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21103212077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551606036 + 10551606037.

It is an arithmetic number, because the mean of its divisors is an integer number (10551606037).

Almost surely, 2^21103212073 is an apocalyptic number.

It is an amenable number.

21103212073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103212073 is an equidigital number, since it uses as much as digits as its factorization.

21103212073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 22.

Adding to 21103212073 its reverse (37021230112), we get a palindrome (58124442185).

The spelling of 21103212073 in words is "twenty-one billion, one hundred three million, two hundred twelve thousand, seventy-three".