21103312123 has 2 divisors, whose sum is σ = 21103312124. Its totient is φ = 21103312122.

The previous prime is 21103312081. The next prime is 21103312133. The reversal of 21103312123 is 32121330112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21103312123 - 2¹³ = 21103303931 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21103312123.

It is not a weakly prime, because it can be changed into another prime (21103312133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551656061 + 10551656062.

It is an arithmetic number, because the mean of its divisors is an integer number (10551656062).

Almost surely, 2^21103312123 is an apocalyptic number.

21103312123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103312123 is an equidigital number, since it uses as much as digits as its factorization.

21103312123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21103312123 its reverse (32121330112), we get a palindrome (53224642235).

The spelling of 21103312123 in words is "twenty-one billion, one hundred three million, three hundred twelve thousand, one hundred twenty-three".