21303112121 has 2 divisors, whose sum is σ = 21303112122. Its totient is φ = 21303112120.

The previous prime is 21303112013. The next prime is 21303112213. The reversal of 21303112121 is 12121130312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16785793600 + 4517318521 = 129560^2 + 67211^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21303112121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21303112121.

It is not a weakly prime, because it can be changed into another prime (21303112421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651556060 + 10651556061.

It is an arithmetic number, because the mean of its divisors is an integer number (10651556061).

Almost surely, 2^21303112121 is an apocalyptic number.

It is an amenable number.

21303112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21303112121 is an equidigital number, since it uses as much as digits as its factorization.

21303112121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21303112121 its reverse (12121130312), we get a palindrome (33424242433).

The spelling of 21303112121 in words is "twenty-one billion, three hundred three million, one hundred twelve thousand, one hundred twenty-one".