1220111221 has 6 divisors (see below), whose sum is σ = 1419313110. Its totient is φ = 1045809576.

The previous prime is 1220111219. The next prime is 1220111231. The reversal of 1220111221 is 1221110221.

It can be written as a sum of positive squares in only one way, i.e., 854919121 + 365192100 = 29239^2 + 19110^2 .

It is not a de Polignac number, because 1220111221 - 2¹ = 1220111219 is a prime.

It is a super-2 number, since 2×1220111221² = 2977342783220221682, 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 (1220111231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12450066 + ... + 12450163.

It is an arithmetic number, because the mean of its divisors is an integer number (236552185).

Almost surely, 2^1220111221 is an apocalyptic number.

It is an amenable number.

1220111221 is a deficient number, since it is larger than the sum of its proper divisors (199201889).

1220111221 is an equidigital number, since it uses as much as digits as its factorization.

1220111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24900243 (or 24900236 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1220111221 is about 34930.0904808447. The cubic root of 1220111221 is about 1068.5621999122.

Adding to 1220111221 its reverse (1221110221), we get a palindrome (2441221442).

The spelling of 1220111221 in words is "one billion, two hundred twenty million, one hundred eleven thousand, two hundred twenty-one".