1221211222201 has 4 divisors (see below), whose sum is σ = 1221215484132. Its totient is φ = 1221206960272.

The previous prime is 1221211222163. The next prime is 1221211222261. The reversal of 1221211222201 is 1022221121221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 88178708601 + 1133032513600 = 296949^2 + 1064440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221211222201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221211222261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1667566 + ... + 2285431.

It is an arithmetic number, because the mean of its divisors is an integer number (305303871033).

Almost surely, 2^{1221211222201} is an apocalyptic number.

It is an amenable number.

1221211222201 is a deficient number, since it is larger than the sum of its proper divisors (4261931).

1221211222201 is an equidigital number, since it uses as much as digits as its factorization.

1221211222201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4261930.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1221211222201 its reverse (1022221121221), we get a palindrome (2243432343422).

The spelling of 1221211222201 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred one".