1221311212000 has 192 divisors, whose sum is σ = 3466122528960. Its totient is φ = 417988608000.

The previous prime is 1221311211997. The next prime is 1221311212007. The reversal of 1221311212000 is 2121131221.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221311212007) 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 31 ways as a sum of consecutive naturals, for example, 68385 + ... + 1564384.

It is an arithmetic number, because the mean of its divisors is an integer number (18052721505).

Almost surely, 2^{1221311212000} is an apocalyptic number.

1221311212000 is a gapful number since it is divisible by the number (10) 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 1221311212000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1733061264480).

1221311212000 is an abundant number, since it is smaller than the sum of its proper divisors (2244811316960).

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

1221311212000 is a wasteful number, since it uses less digits than its factorization.

1221311212000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632822 (or 1632804 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 1221311212000 its reverse (2121131221), we get a palindrome (1223432343221).

The spelling of 1221311212000 in words is "one trillion, two hundred twenty-one billion, three hundred eleven million, two hundred twelve thousand".