1211201111 has 4 divisors (see below), whose sum is σ = 1211593800. Its totient is φ = 1210808424.

The previous prime is 1211201107. The next prime is 1211201207. The reversal of 1211201111 is 1111021121.

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 1211201111 - 2² = 1211201107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211201092 and 1211201101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211201011) 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, 191681 + ... + 197898.

It is an arithmetic number, because the mean of its divisors is an integer number (302898450).

Almost surely, 2^1211201111 is an apocalyptic number.

1211201111 is a deficient number, since it is larger than the sum of its proper divisors (392689).

1211201111 is an equidigital number, since it uses as much as digits as its factorization.

1211201111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392688.

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

The square root of 1211201111 is about 34802.3147362356. The cubic root of 1211201111 is about 1065.9547115050.

Adding to 1211201111 its reverse (1111021121), we get a palindrome (2322222232).

The spelling of 1211201111 in words is "one billion, two hundred eleven million, two hundred one thousand, one hundred eleven".