1221000212000 has 96 divisors (see below), whose sum is σ = 3005548129584. Its totient is φ = 487496448000.

The previous prime is 1221000211999. The next prime is 1221000212009. The reversal of 1221000212000 is 2120001221.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 1731856 + 1220998480144 = 1316^2 + 1104988^2 .

It is not an unprimeable number, because it can be changed into a prime (1221000212009) 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, 1881884 + ... + 2446116.

Almost surely, 2^{1221000212000} is an apocalyptic number.

1221000212000 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 1221000212000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1502774064792).

1221000212000 is an abundant number, since it is smaller than the sum of its proper divisors (1784547917584).

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

1221000212000 is an equidigital number, since it uses as much as digits as its factorization.

1221000212000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564799 (or 564781 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1221000212000 its reverse (2120001221), we get a palindrome (1223120213221).

The spelling of 1221000212000 in words is "one trillion, two hundred twenty-one billion, two hundred twelve thousand".