21102120073 has 2 divisors, whose sum is σ = 21102120074. Its totient is φ = 21102120072.

The previous prime is 21102120071. The next prime is 21102120101. The reversal of 21102120073 is 37002120112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20597129289 + 504990784 = 143517^2 + 22472^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102120073 - 2¹ = 21102120071 is a prime.

Together with 21102120071, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21102120073.

It is not a weakly prime, because it can be changed into another prime (21102120071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551060036 + 10551060037.

It is an arithmetic number, because the mean of its divisors is an integer number (10551060037).

Almost surely, 2^21102120073 is an apocalyptic number.

It is an amenable number.

21102120073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102120073 is an equidigital number, since it uses as much as digits as its factorization.

21102120073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168, while the sum is 19.

Adding to 21102120073 its reverse (37002120112), we get a palindrome (58104240185).

The spelling of 21102120073 in words is "twenty-one billion, one hundred two million, one hundred twenty thousand, seventy-three".