1211322221 has 4 divisors (see below), whose sum is σ = 1211465244. Its totient is φ = 1211179200.

The previous prime is 1211322197. The next prime is 1211322239. The reversal of 1211322221 is 1222231121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1222231121 = 19423 ⋅62927.

It can be written as a sum of positive squares in 2 ways, for example, as 1207562500 + 3759721 = 34750^2 + 1939^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211322221 - 2⁶ = 1211322157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211322221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211328221) 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, 57950 + ... + 76031.

It is an arithmetic number, because the mean of its divisors is an integer number (302866311).

Almost surely, 2^1211322221 is an apocalyptic number.

It is an amenable number.

1211322221 is a deficient number, since it is larger than the sum of its proper divisors (143023).

1211322221 is an equidigital number, since it uses as much as digits as its factorization.

1211322221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143022.

The product of its digits is 96, while the sum is 17.

The square root of 1211322221 is about 34804.0546632142. The cubic root of 1211322221 is about 1065.9902391784.

Adding to 1211322221 its reverse (1222231121), we get a palindrome (2433553342).

The spelling of 1211322221 in words is "one billion, two hundred eleven million, three hundred twenty-two thousand, two hundred twenty-one".