It is a self number, because there is not a number n which added to its sum of digits gives 121220111220999.
It is a congruent number.
Almost surely, 2121220111220999 is an apocalyptic number.
121220111220999 is a wasteful number, since it uses less digits than its factorization.
121220111220999 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 4073267.
The spelling of 121220111220999 in words is "one hundred twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty thousand, nine hundred ninety-nine".