1212221121 has 16 divisors (see below), whose sum is σ = 1665432384. Its totient is φ = 783722304.

The previous prime is 1212221119. The next prime is 1212221149. The reversal of 1212221121 is 1211222121.

It is not a de Polignac number, because 1212221121 - 2¹ = 1212221119 is a prime.

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 1212221121.

It is not an unprimeable number, because it can be changed into a prime (1212221191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16291 + ... + 51863.

It is an arithmetic number, because the mean of its divisors is an integer number (104089524).

Almost surely, 2^1212221121 is an apocalyptic number.

It is an amenable number.

1212221121 is a deficient number, since it is larger than the sum of its proper divisors (453211263).

1212221121 is a wasteful number, since it uses less digits than its factorization.

1212221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35920.

The product of its digits is 32, while the sum is 15.

The square root of 1212221121 is about 34816.9659936072. The cubic root of 1212221121 is about 1066.2538579143.

Adding to 1212221121 its reverse (1211222121), we get a palindrome (2423443242).

The spelling of 1212221121 in words is "one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred twenty-one".