1221122202221 has 8 divisors (see below), whose sum is σ = 1223237826360. Its totient is φ = 1219006769152.

The previous prime is 1221122202173. The next prime is 1221122202271. The reversal of 1221122202221 is 1222022211221.

It can be written as a sum of positive squares in 4 ways, for example, as 770866440100 + 450255762121 = 877990^2 + 671011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221122202221 - 2¹⁰ = 1221122201197 is a prime.

It is a super-2 number, since 2×1221122202221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221122202193 and 1221122202202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221122202271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19854365 + ... + 19915773.

It is an arithmetic number, because the mean of its divisors is an integer number (152904728295).

Almost surely, 2^{1221122202221} is an apocalyptic number.

It is an amenable number.

1221122202221 is a deficient number, since it is larger than the sum of its proper divisors (2115624139).

1221122202221 is an equidigital number, since it uses as much as digits as its factorization.

1221122202221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95535.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 1221122202221 its reverse (1222022211221), we get a palindrome (2443144413442).

The spelling of 1221122202221 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred two thousand, two hundred twenty-one".