21123032111 has 2 divisors, whose sum is σ = 21123032112. Its totient is φ = 21123032110.

The previous prime is 21123032057. The next prime is 21123032143. The reversal of 21123032111 is 11123032112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123032111 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21123032111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123032171) 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, 10561516055 + 10561516056.

It is an arithmetic number, because the mean of its divisors is an integer number (10561516056).

Almost surely, 2^21123032111 is an apocalyptic number.

21123032111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123032111 is an equidigital number, since it uses as much as digits as its factorization.

21123032111 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21123032111 its reverse (11123032112), we get a palindrome (32246064223).

Subtracting from 21123032111 its reverse (11123032112), we obtain a palindrome (9999999999).

The spelling of 21123032111 in words is "twenty-one billion, one hundred twenty-three million, thirty-two thousand, one hundred eleven".