1211100111 has 24 divisors (see below), whose sum is σ = 1994756400. Its totient is φ = 701450496.

The previous prime is 1211100101. The next prime is 1211100113. The reversal of 1211100111 is 1110011121.

It is not a de Polignac number, because 1211100111 - 2⁶ = 1211100047 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 1211100093 and 1211100102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211100113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 302461 + ... + 306438.

It is an arithmetic number, because the mean of its divisors is an integer number (83114850).

Almost surely, 2^1211100111 is an apocalyptic number.

1211100111 is a deficient number, since it is larger than the sum of its proper divisors (783656289).

1211100111 is a wasteful number, since it uses less digits than its factorization.

1211100111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608935 (or 608932 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

The square root of 1211100111 is about 34800.8636530762. The cubic root of 1211100111 is about 1065.9250812981.

Adding to 1211100111 its reverse (1110011121), we get a palindrome (2321111232).

The spelling of 1211100111 in words is "one billion, two hundred eleven million, one hundred thousand, one hundred eleven".