111111221 has 16 divisors (see below), whose sum is σ = 127142400. Its totient is φ = 96251328.

The previous prime is 111111199. The next prime is 111111233. The reversal of 111111221 is 122111111.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111111221 is a prime.

It is a super-2 number, since 2×111111221² = 24691406864221682, which 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 (111111421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24860 + ... + 28986.

It is an arithmetic number, because the mean of its divisors is an integer number (7946400).

Almost surely, 2^111111221 is an apocalyptic number.

It is an amenable number.

111111221 is a deficient number, since it is larger than the sum of its proper divisors (16031179).

111111221 is a wasteful number, since it uses less digits than its factorization.

111111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4268.

The product of its digits is 4, while the sum is 11.

The square root of 111111221 is about 10540.9307463810. The cubic root of 111111221 is about 480.7500152563.

Adding to 111111221 its reverse (122111111), we get a palindrome (233222332).

It can be divided in two parts, 11111 and 1221, that multiplied together give a palindrome (13566531).

The spelling of 111111221 in words is "one hundred eleven million, one hundred eleven thousand, two hundred twenty-one".