1221133211 has 4 divisors (see below), whose sum is σ = 1285403400. Its totient is φ = 1156863024.

The previous prime is 1221133159. The next prime is 1221133231. The reversal of 1221133211 is 1123311221.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221133211 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221133211.

It is not an unprimeable number, because it can be changed into a prime (1221133231) 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, 32135066 + ... + 32135103.

It is an arithmetic number, because the mean of its divisors is an integer number (321350850).

Almost surely, 2^1221133211 is an apocalyptic number.

1221133211 is a deficient number, since it is larger than the sum of its proper divisors (64270189).

1221133211 is an equidigital number, since it uses as much as digits as its factorization.

1221133211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64270188.

The product of its digits is 72, while the sum is 17.

The square root of 1221133211 is about 34944.7164962030. The cubic root of 1221133211 is about 1068.8604664678.

Adding to 1221133211 its reverse (1123311221), we get a palindrome (2344444432).

The spelling of 1221133211 in words is "one billion, two hundred twenty-one million, one hundred thirty-three thousand, two hundred eleven".