1001221221000 has 1024 divisors, whose sum is σ = 4308041687040. Its totient is φ = 186831360000.

The previous prime is 1001221220999. The next prime is 1001221221023. The reversal of 1001221221000 is 1221221001.

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

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 111106495 + ... + 111115505.

It is an arithmetic number, because the mean of its divisors is an integer number (4207071960).

Almost surely, 2^{1001221221000} is an apocalyptic number.

1001221221000 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 1001221221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2154020843520).

1001221221000 is an abundant number, since it is smaller than the sum of its proper divisors (3306820466040).

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

1001221221000 is a wasteful number, since it uses less digits than its factorization.

1001221221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9103 (or 9089 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 1001221221000 its reverse (1221221001), we get a palindrome (1002442442001).

Subtracting from 1001221221000 its reverse (1221221001), we obtain a palindrome (999999999999).

It can be divided in two parts, 1001221 and 221000, that added together give a palindrome (1222221).

The spelling of 1001221221000 in words is "one trillion, one billion, two hundred twenty-one million, two hundred twenty-one thousand".