1211222121121 has 4 divisors (see below), whose sum is σ = 1211980558612. Its totient is φ = 1210463683632.

The previous prime is 1211222121113. The next prime is 1211222121227. The reversal of 1211222121121 is 1211212221121.

It is a happy number.

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 609804810000 + 601417311121 = 780900^2 + 775511^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211222121121 - 2³ = 1211222121113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211222181121) 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, 379216350 + ... + 379219543.

It is an arithmetic number, because the mean of its divisors is an integer number (302995139653).

Almost surely, 2^{1211222121121} is an apocalyptic number.

It is an amenable number.

1211222121121 is a deficient number, since it is larger than the sum of its proper divisors (758437491).

1211222121121 is an equidigital number, since it uses as much as digits as its factorization.

1211222121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 758437490.

The product of its digits is 64, while the sum is 19.

Adding to 1211222121121 its reverse (1211212221121), we get a palindrome (2422434342242).

The spelling of 1211222121121 in words is "one trillion, two hundred eleven billion, two hundred twenty-two million, one hundred twenty-one thousand, one hundred twenty-one".