1211220211 has 4 divisors (see below), whose sum is σ = 1211301000. Its totient is φ = 1211139424.

The previous prime is 1211220193. The next prime is 1211220217. The reversal of 1211220211 is 1120221121.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1211220211 - 2⁷ = 1211220083 is a prime.

It is a super-4 number, since 4×1211220211⁴ (a number of 37 digits) contains 4444 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211220191 and 1211220200.

It is not an unprimeable number, because it can be changed into a prime (1211220217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10561 + ... + 50338.

It is an arithmetic number, because the mean of its divisors is an integer number (302825250).

Almost surely, 2^1211220211 is an apocalyptic number.

1211220211 is a deficient number, since it is larger than the sum of its proper divisors (80789).

1211220211 is an equidigital number, since it uses as much as digits as its factorization.

1211220211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80788.

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

The square root of 1211220211 is about 34802.5891421888. The cubic root of 1211220211 is about 1065.9603146559.

Adding to 1211220211 its reverse (1120221121), we get a palindrome (2331441332).

It can be divided in two parts, 12112 and 20211, that added together give a palindrome (32323).

The spelling of 1211220211 in words is "one billion, two hundred eleven million, two hundred twenty thousand, two hundred eleven".