21111010121111 has 2 divisors, whose sum is σ = 21111010121112. Its totient is φ = 21111010121110.

The previous prime is 21111010121087. The next prime is 21111010121129. The reversal of 21111010121111 is 11112101011112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21111010121111 - 2²² = 21111005926807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111010121171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555505060555 + 10555505060556.

It is an arithmetic number, because the mean of its divisors is an integer number (10555505060556).

Almost surely, 2^{21111010121111} is an apocalyptic number.

21111010121111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111010121111 is an equidigital number, since it uses as much as digits as its factorization.

21111010121111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 14.

Adding to 21111010121111 its reverse (11112101011112), we get a palindrome (32223111132223).

The spelling of 21111010121111 in words is "twenty-one trillion, one hundred eleven billion, ten million, one hundred twenty-one thousand, one hundred eleven".