1220212221221 has 24 divisors (see below), whose sum is σ = 1434118565880. Its totient is φ = 1035082608000.

The previous prime is 1220212221209. The next prime is 1220212221227. The reversal of 1220212221221 is 1221222120221.

It can be written as a sum of positive squares in 4 ways, for example, as 1023160572196 + 197051649025 = 1011514^2 + 443905^2 .

It is not a de Polignac number, because 1220212221221 - 2¹⁰ = 1220212220197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1220212221193 and 1220212221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220212221227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11373851 + ... + 11480631.

It is an arithmetic number, because the mean of its divisors is an integer number (59754940245).

Almost surely, 2^{1220212221221} is an apocalyptic number.

It is an amenable number.

1220212221221 is a deficient number, since it is larger than the sum of its proper divisors (213906344659).

1220212221221 is a wasteful number, since it uses less digits than its factorization.

1220212221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109205 (or 109198 counting only the distinct ones).

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

Adding to 1220212221221 its reverse (1221222120221), we get a palindrome (2441434341442).

The spelling of 1220212221221 in words is "one trillion, two hundred twenty billion, two hundred twelve million, two hundred twenty-one thousand, two hundred twenty-one".