21111110231 has 2 divisors, whose sum is σ = 21111110232. Its totient is φ = 21111110230.

The previous prime is 21111110161. The next prime is 21111110261. The reversal of 21111110231 is 13201111112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111110231 is a prime.

It is a super-3 number, since 3×21111110231³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111110261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555555115 + 10555555116.

It is an arithmetic number, because the mean of its divisors is an integer number (10555555116).

Almost surely, 2^21111110231 is an apocalyptic number.

21111110231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111110231 is an equidigital number, since it uses as much as digits as its factorization.

21111110231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 21111110231 its reverse (13201111112), we get a palindrome (34312221343).

The spelling of 21111110231 in words is "twenty-one billion, one hundred eleven million, one hundred ten thousand, two hundred thirty-one".