1221011101221 has 16 divisors (see below), whose sum is σ = 1687641528384. Its totient is φ = 784605256704.

The previous prime is 1221011101213. The next prime is 1221011101241.

It is a happy number.

1221011101221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1221011101221 - 2³ = 1221011101213 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221011101221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011101241) 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, 51390460 + ... + 51414213.

It is an arithmetic number, because the mean of its divisors is an integer number (105477595524).

Almost surely, 2^{1221011101221} is an apocalyptic number.

It is an amenable number.

1221011101221 is a deficient number, since it is larger than the sum of its proper divisors (466630427163).

1221011101221 is a wasteful number, since it uses less digits than its factorization.

1221011101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102804820.

The product of its (nonzero) digits is 16, while the sum is 15.

The spelling of 1221011101221 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred one thousand, two hundred twenty-one".