21121110101111 has 2 divisors, whose sum is σ = 21121110101112. Its totient is φ = 21121110101110.

The previous prime is 21121110101087. The next prime is 21121110101303. The reversal of 21121110101111 is 11110101112112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121110101111 - 2¹⁸ = 21121109838967 is a prime.

It is a super-2 number, since 2×21121110101111² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121110101011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560555050555 + 10560555050556.

It is an arithmetic number, because the mean of its divisors is an integer number (10560555050556).

Almost surely, 2^{21121110101111} is an apocalyptic number.

21121110101111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121110101111 is an equidigital number, since it uses as much as digits as its factorization.

21121110101111 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 21121110101111 its reverse (11110101112112), we get a palindrome (32231211213223).

The spelling of 21121110101111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, one hundred one thousand, one hundred eleven".