1220221 has 4 divisors (see below), whose sum is σ = 1225692. Its totient is φ = 1214752.

The previous prime is 1220203. The next prime is 1220239.

1220221 is nontrivially palindromic in base 10.

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

It is an interprime number because it is at equal distance from previous prime (1220203) and next prime (1220239).

It can be written as a sum of positive squares in 2 ways, for example, as 657721 + 562500 = 811^2 + 750^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220221 - 2¹⁵ = 1187453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220198 and 1220207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2386 + ... + 2851.

It is an arithmetic number, because the mean of its divisors is an integer number (306423).

2^1220221 is an apocalyptic number.

It is an amenable number.

1220221 is a deficient number, since it is larger than the sum of its proper divisors (5471).

1220221 is an equidigital number, since it uses as much as digits as its factorization.

1220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5470.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 1220221 is about 1104.6361391879. The cubic root of 1220221 is about 106.8594246764.

It can be divided in two parts, 1220 and 221, that added together give a palindrome (1441).

The spelling of 1220221 in words is "one million, two hundred twenty thousand, two hundred twenty-one".