221101211111111 has 4 divisors (see below), whose sum is σ = 221101242257352. Its totient is φ = 221101179964872.

The previous prime is 221101211111101. The next prime is 221101211111159. The reversal of 221101211111111 is 111111112101122.

It is a happy number.

221101211111111 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221101211111111 is a prime.

It is a Duffinian number.

221101211111111 is a modest number, since divided by 11111111 gives 2211012 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 221101211111111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221101211111101) 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, 844160 + ... + 21045546.

It is an arithmetic number, because the mean of its divisors is an integer number (55275310564338).

Almost surely, 2^{221101211111111} is an apocalyptic number.

221101211111111 is a deficient number, since it is larger than the sum of its proper divisors (31146241).

221101211111111 is a wasteful number, since it uses less digits than its factorization.

221101211111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31146240.

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

Adding to 221101211111111 its reverse (111111112101122), we get a palindrome (332212323212233).

The spelling of 221101211111111 in words is "two hundred twenty-one trillion, one hundred one billion, two hundred eleven million, one hundred eleven thousand, one hundred eleven".