1211222100221 has 16 divisors (see below), whose sum is σ = 1385301187200. Its totient is φ = 1037405119680.

The previous prime is 1211222100211. The next prime is 1211222100239. The reversal of 1211222100221 is 1220012221121.

It is a cyclic number.

It is not a de Polignac number, because 1211222100221 - 2²² = 1211217905917 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 1211222100221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211222100211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89866535 + ... + 89880011.

It is an arithmetic number, because the mean of its divisors is an integer number (86581324200).

Almost surely, 2^{1211222100221} is an apocalyptic number.

It is an amenable number.

1211222100221 is a deficient number, since it is larger than the sum of its proper divisors (174079086979).

1211222100221 is a wasteful number, since it uses less digits than its factorization.

1211222100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22244.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1211222100221 its reverse (1220012221121), we get a palindrome (2431234321342).

The spelling of 1211222100221 in words is "one trillion, two hundred eleven billion, two hundred twenty-two million, one hundred thousand, two hundred twenty-one".