1220211121 has 4 divisors (see below), whose sum is σ = 1240214644. Its totient is φ = 1200207600.

The previous prime is 1220211077. The next prime is 1220211151. The reversal of 1220211121 is 1211120221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 235192896 + 985018225 = 15336^2 + 31385^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220211121 - 2¹⁷ = 1220080049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220211151) 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, 10001670 + ... + 10001791.

It is an arithmetic number, because the mean of its divisors is an integer number (310053661).

Almost surely, 2^1220211121 is an apocalyptic number.

It is an amenable number.

1220211121 is a deficient number, since it is larger than the sum of its proper divisors (20003523).

1220211121 is an equidigital number, since it uses as much as digits as its factorization.

1220211121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20003522.

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

The square root of 1220211121 is about 34931.5204507333. The cubic root of 1220211121 is about 1068.5913629504.

Adding to 1220211121 its reverse (1211120221), we get a palindrome (2431331342).

The spelling of 1220211121 in words is "one billion, two hundred twenty million, two hundred eleven thousand, one hundred twenty-one".