121221100221 has 16 divisors (see below), whose sum is σ = 177011257920. Its totient is φ = 73333232640.

The previous prime is 121221100183. The next prime is 121221100223. The reversal of 121221100221 is 122001122121.

It is not a de Polignac number, because 121221100221 - 2²⁷ = 121086882493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121221100221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121221100223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26338660 + ... + 26343261.

It is an arithmetic number, because the mean of its divisors is an integer number (11063203620).

Almost surely, 2^121221100221 is an apocalyptic number.

It is an amenable number.

121221100221 is a deficient number, since it is larger than the sum of its proper divisors (55790157699).

121221100221 is a wasteful number, since it uses less digits than its factorization.

121221100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52681996.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 121221100221 its reverse (122001122121), we get a palindrome (243222222342).

The spelling of 121221100221 in words is "one hundred twenty-one billion, two hundred twenty-one million, one hundred thousand, two hundred twenty-one".