1223220221 has 4 divisors (see below), whose sum is σ = 1226725500. Its totient is φ = 1219714944.

The previous prime is 1223220197. The next prime is 1223220233. The reversal of 1223220221 is 1220223221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1220223221 = 7 ⋅174317603.

It can be written as a sum of positive squares in 2 ways, for example, as 319015321 + 904204900 = 17861^2 + 30070^2 .

It is a cyclic number.

It is not a de Polignac number, because 1223220221 - 2³⁰ = 149478397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1223220221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1223220241) 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 3 ways as a sum of consecutive naturals, for example, 1752116 + ... + 1752813.

It is an arithmetic number, because the mean of its divisors is an integer number (306681375).

Almost surely, 2^1223220221 is an apocalyptic number.

It is an amenable number.

1223220221 is a deficient number, since it is larger than the sum of its proper divisors (3505279).

1223220221 is an equidigital number, since it uses as much as digits as its factorization.

1223220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3505278.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1223220221 is about 34974.5653439753. The cubic root of 1223220221 is about 1069.4690413124.

Adding to 1223220221 its reverse (1220223221), we get a palindrome (2443443442).

The spelling of 1223220221 in words is "one billion, two hundred twenty-three million, two hundred twenty thousand, two hundred twenty-one".