221111211011111 has 4 divisors (see below), whose sum is σ = 234117752835312. Its totient is φ = 208104669186912.

The previous prime is 221111211011021. The next prime is 221111211011113. The reversal of 221111211011111 is 111110112111122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221111211011111 - 2³⁴ = 221094031141927 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 13006541824183 = 221111211011111 / (2 + 2 + 1 + 1 + 1 + 1 + 2 + 1 + 1 + 0 + 1 + 1 + 1 + 1 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221111211011111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221111211011113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6503270912075 + ... + 6503270912108.

It is an arithmetic number, because the mean of its divisors is an integer number (58529438208828).

Almost surely, 2^{221111211011111} is an apocalyptic number.

221111211011111 is a deficient number, since it is larger than the sum of its proper divisors (13006541824201).

221111211011111 is a wasteful number, since it uses less digits than its factorization.

221111211011111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13006541824200.

The product of its (nonzero) digits is 8, while the sum is 17.

Adding to 221111211011111 its reverse (111110112111122), we get a palindrome (332221323122233).

The spelling of 221111211011111 in words is "two hundred twenty-one trillion, one hundred eleven billion, two hundred eleven million, eleven thousand, one hundred eleven".