1221001320000 has 1680 divisors, whose sum is σ = 5212583139456. Its totient is φ = 246681600000.

The previous prime is 1221001319929. The next prime is 1221001320001. The reversal of 1221001320000 is 231001221.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (1221001320001) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 4167239854 + ... + 4167240146.

Almost surely, 2^{1221001320000} is an apocalyptic number.

1221001320000 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 1221001320000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2606291569728).

1221001320000 is an abundant number, since it is smaller than the sum of its proper divisors (3991581819456).

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

1221001320000 is a wasteful number, since it uses less digits than its factorization.

1221001320000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 362 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 1221001320000 its reverse (231001221), we get a palindrome (1221232321221).

The spelling of 1221001320000 in words is "one trillion, two hundred twenty-one billion, one million, three hundred twenty thousand".