1221100110012 has 96 divisors (see below), whose sum is σ = 3099196634688. Its totient is φ = 372637200384.

The previous prime is 1221100110007. The next prime is 1221100110019. The reversal of 1221100110012 is 2100110011221.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1221100110012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221100110019) 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, 31357578 + ... + 31396494.

It is an arithmetic number, because the mean of its divisors is an integer number (32283298278).

Almost surely, 2^{1221100110012} is an apocalyptic number.

1221100110012 is a gapful number since it is divisible by the number (12) 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 1221100110012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1549598317344).

1221100110012 is an abundant number, since it is smaller than the sum of its proper divisors (1878096524676).

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

1221100110012 is a wasteful number, since it uses less digits than its factorization.

1221100110012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43135 (or 43133 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 1221100110012 its reverse (2100110011221), we get a palindrome (3321210121233).

The spelling of 1221100110012 in words is "one trillion, two hundred twenty-one billion, one hundred million, one hundred ten thousand, twelve".