1221221200212 has 216 divisors, whose sum is σ = 3458205544248. Its totient is φ = 362958336000.

The previous prime is 1221221200211. The next prime is 1221221200217. The reversal of 1221221200212 is 2120021221221.

It is a happy number.

1221221200212 is a `hidden beast` number, since 1 + 221 + 221 + 200 + 21 + 2 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 986358840336 + 234862359876 = 993156^2 + 484626^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221200211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 25169608 + ... + 25218080.

It is an arithmetic number, because the mean of its divisors is an integer number (16010210853).

Almost surely, 2^{1221221200212} is an apocalyptic number.

1221221200212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221221200212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1729102772124).

1221221200212 is an abundant number, since it is smaller than the sum of its proper divisors (2236984344036).

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

1221221200212 is a wasteful number, since it uses less digits than its factorization.

1221221200212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48651 (or 48633 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221221200212 its reverse (2120021221221), we get a palindrome (3341242421433).

The spelling of 1221221200212 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred thousand, two hundred twelve".