1220111111 has 4 divisors (see below), whose sum is σ = 1248485832. Its totient is φ = 1191736392.

The previous prime is 1220111099. The next prime is 1220111119. The reversal of 1220111111 is 1111110221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1220111111 - 2²⁶ = 1153002247 is a prime.

It is a super-2 number, since 2×1220111111² = 2977342246371308642, which contains 22 as substring.

It is a Duffinian number.

1220111111 is a modest number, since divided by 111111 gives 1220 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 1220111092 and 1220111101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220111119) 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, 14187296 + ... + 14187381.

It is an arithmetic number, because the mean of its divisors is an integer number (312121458).

Almost surely, 2^1220111111 is an apocalyptic number.

1220111111 is a deficient number, since it is larger than the sum of its proper divisors (28374721).

1220111111 is an equidigital number, since it uses as much as digits as its factorization.

1220111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28374720.

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

The square root of 1220111111 is about 34930.0889062711. The cubic root of 1220111111 is about 1068.5621677999.

Adding to 1220111111 its reverse (1111110221), we get a palindrome (2331221332).

The spelling of 1220111111 in words is "one billion, two hundred twenty million, one hundred eleven thousand, one hundred eleven".