111111221221 has 32 divisors (see below), whose sum is σ = 149381358336. Its totient is φ = 79814592000.

The previous prime is 111111221219. The next prime is 111111221237. The reversal of 111111221221 is 122122111111.

It is not a de Polignac number, because 111111221221 - 2¹ = 111111221219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 111111221195 and 111111221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111111221251) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 688831 + ... + 834691.

It is an arithmetic number, because the mean of its divisors is an integer number (4668167448).

Almost surely, 2^111111221221 is an apocalyptic number.

111111221221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

111111221221 is a deficient number, since it is larger than the sum of its proper divisors (38270137115).

111111221221 is a wasteful number, since it uses less digits than its factorization.

111111221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146653.

The product of its digits is 16, while the sum is 16.

Adding to 111111221221 its reverse (122122111111), we get a palindrome (233233332332).

It can be divided in two parts, 11111 and 1221221, that multiplied together give a palindrome (13568986531).

The spelling of 111111221221 in words is "one hundred eleven billion, one hundred eleven million, two hundred twenty-one thousand, two hundred twenty-one".