21121111001111 has 16 divisors (see below), whose sum is σ = 24397053355008. Its totient is φ = 18071186275200.

The previous prime is 21121111001083. The next prime is 21121111001129. The reversal of 21121111001111 is 11110011112112.

It is a cyclic number.

It is not a de Polignac number, because 21121111001111 - 2⁶ = 21121111001047 is a prime.

It is a super-2 number, since 2×21121111001111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111001161) 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 in 15 ways as a sum of consecutive naturals, for example, 8744096 + ... + 10895018.

It is an arithmetic number, because the mean of its divisors is an integer number (1524815834688).

Almost surely, 2^{21121111001111} is an apocalyptic number.

21121111001111 is a deficient number, since it is larger than the sum of its proper divisors (3275942353897).

21121111001111 is a wasteful number, since it uses less digits than its factorization.

21121111001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2203462.

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

Adding to 21121111001111 its reverse (11110011112112), we get a palindrome (32231122113223).

It can be divided in two parts, 2112 and 1111001111, that multiplied together give a palindrome (2346434346432).

The spelling of 21121111001111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, one thousand, one hundred eleven".