1221212221212 has 24 divisors (see below), whose sum is σ = 2918995066512. Its totient is φ = 397142185600.

The previous prime is 1221212221199. The next prime is 1221212221217. The reversal of 1221212221212 is 2121222121221.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221212221217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1241068839 + ... + 1241069822.

It is an arithmetic number, because the mean of its divisors is an integer number (121624794438).

Almost surely, 2^{1221212221212} is an apocalyptic number.

1221212221212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221212221212 is an abundant number, since it is smaller than the sum of its proper divisors (1697782845300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221212221212 is a wasteful number, since it uses less digits than its factorization.

1221212221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2482138709 (or 2482138707 counting only the distinct ones).

The product of its digits is 256, while the sum is 21.

Adding to 1221212221212 its reverse (2121222121221), we get a palindrome (3342434342433).

Subtracting 1221212221212 from its reverse (2121222121221), we obtain a palindrome (900009900009).

The spelling of 1221212221212 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, two hundred twelve".