21102028111 has 2 divisors, whose sum is σ = 21102028112. Its totient is φ = 21102028110.

The previous prime is 21102028091. The next prime is 21102028127. The reversal of 21102028111 is 11182020112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21102028111 - 2⁹ = 21102027599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102028511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551014055 + 10551014056.

It is an arithmetic number, because the mean of its divisors is an integer number (10551014056).

Almost surely, 2^21102028111 is an apocalyptic number.

21102028111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102028111 is an equidigital number, since it uses as much as digits as its factorization.

21102028111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21102028111 its reverse (11182020112), we get a palindrome (32284048223).

The spelling of 21102028111 in words is "twenty-one billion, one hundred two million, twenty-eight thousand, one hundred eleven".