It is a semiprime because it is the product of two primes.
It is a self number, because there is not a number n which added to its sum of digits gives 221421255544718.
It is a congruent number.
Almost surely, 2221421255544718 is an apocalyptic number.
221421255544718 is a wasteful number, since it uses less digits than its factorization.
221421255544718 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 110710627772361.
The spelling of 221421255544718 in words is "two hundred twenty-one trillion, four hundred twenty-one billion, two hundred fifty-five million, five hundred forty-four thousand, seven hundred eighteen".