1221111 has 24 divisors (see below), whose sum is σ = 1916720. Its totient is φ = 746496.

The previous prime is 1221097. The next prime is 1221113. The reversal of 1221111 is 1111221.

It is a happy number.

It is not a de Polignac number, because 1221111 - 2⁵ = 1221079 is a prime.

It is a super-2 number, since 2×1221111² = 2982224148642, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

1221111 is a modest number, since divided by 1111 gives 122 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 1221093 and 1221102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221113) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6231 + ... + 6423.

2^1221111 is an apocalyptic number.

1221111 is a deficient number, since it is larger than the sum of its proper divisors (695609).

1221111 is a wasteful number, since it uses less digits than its factorization.

1221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255 (or 252 counting only the distinct ones).

The product of its digits is 4, while the sum is 9.

The square root of 1221111 is about 1105.0389133420. The cubic root of 1221111 is about 106.8853985984.

Adding to 1221111 its reverse (1111221), we get a palindrome (2332332).

It can be divided in two parts, 1221 and 111, that multiplied together give a palindrome (135531).

The spelling of 1221111 in words is "one million, two hundred twenty-one thousand, one hundred eleven".