1212211221 has 16 divisors (see below), whose sum is σ = 1743981120. Its totient is φ = 744531840.

The previous prime is 1212211213. The next prime is 1212211241. The reversal of 1212211221 is 1221122121.

It is not a de Polignac number, because 1212211221 - 2³ = 1212211213 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 1212211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212211201) 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, 9511 + ... + 50148.

It is an arithmetic number, because the mean of its divisors is an integer number (108998820).

Almost surely, 2^1212211221 is an apocalyptic number.

It is an amenable number.

1212211221 is a deficient number, since it is larger than the sum of its proper divisors (531769899).

1212211221 is a wasteful number, since it uses less digits than its factorization.

1212211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60196.

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

The square root of 1212211221 is about 34816.8238212506. The cubic root of 1212211221 is about 1066.2509552695.

Adding to 1212211221 its reverse (1221122121), we get a palindrome (2433333342).

It can be divided in two parts, 121221 and 1221, that multiplied together give a palindrome (148010841).

The spelling of 1212211221 in words is "one billion, two hundred twelve million, two hundred eleven thousand, two hundred twenty-one".