1221100112000 has 128 divisors (see below), whose sum is σ = 3046775500080. Its totient is φ = 486700032000.

The previous prime is 1221100111999. The next prime is 1221100112033. The reversal of 1221100112000 is 2110011221.

It can be written as a sum of positive squares in 8 ways, for example, as 16427036224 + 1204673075776 = 128168^2 + 1097576^2 .

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4360202 + ... + 4631798.

Almost surely, 2^{1221100112000} is an apocalyptic number.

1221100112000 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 1221100112000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1523387750040).

1221100112000 is an abundant number, since it is smaller than the sum of its proper divisors (1825675388080).

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

1221100112000 is an equidigital number, since it uses as much as digits as its factorization.

1221100112000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271907 (or 271885 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221100112000 its reverse (2110011221), we get a palindrome (1223210123221).

The spelling of 1221100112000 in words is "one trillion, two hundred twenty-one billion, one hundred million, one hundred twelve thousand".