21210305111 has 2 divisors, whose sum is σ = 21210305112. Its totient is φ = 21210305110.

The previous prime is 21210305107. The next prime is 21210305141. The reversal of 21210305111 is 11150301212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21210305111 - 2² = 21210305107 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210305111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210305141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605152555 + 10605152556.

It is an arithmetic number, because the mean of its divisors is an integer number (10605152556).

Almost surely, 2^21210305111 is an apocalyptic number.

21210305111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210305111 is an equidigital number, since it uses as much as digits as its factorization.

21210305111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 17.

Adding to 21210305111 its reverse (11150301212), we get a palindrome (32360606323).

The spelling of 21210305111 in words is "twenty-one billion, two hundred ten million, three hundred five thousand, one hundred eleven".