1211221011221 has 16 divisors (see below), whose sum is σ = 1316620905600. Its totient is φ = 1107572211648.

The previous prime is 1211221011181. The next prime is 1211221011229. The reversal of 1211221011221 is 1221101221121.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211221011221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211221011221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211221011229) 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, 7256120 + ... + 7421166.

It is an arithmetic number, because the mean of its divisors is an integer number (82288806600).

Almost surely, 2^{1211221011221} is an apocalyptic number.

It is an amenable number.

1211221011221 is a deficient number, since it is larger than the sum of its proper divisors (105399894379).

1211221011221 is a wasteful number, since it uses less digits than its factorization.

1211221011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170348.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1211221011221 its reverse (1221101221121), we get a palindrome (2432322232342).

The spelling of 1211221011221 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, eleven thousand, two hundred twenty-one".