220428221 has 6 divisors (see below), whose sum is σ = 238688730. Its totient is φ = 203472048.

The previous prime is 220428209. The next prime is 220428227. The reversal of 220428221 is 122824022.

It can be written as a sum of positive squares in 3 ways, for example, as 4044121 + 216384100 = 2011^2 + 14710^2 .

It is not a de Polignac number, because 220428221 - 2¹⁸ = 220166077 is a prime.

It is a super-2 number, since 2×220428221² = 97177201226449682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220428227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 651986 + ... + 652323.

It is an arithmetic number, because the mean of its divisors is an integer number (39781455).

Almost surely, 2^220428221 is an apocalyptic number.

It is an amenable number.

220428221 is a deficient number, since it is larger than the sum of its proper divisors (18260509).

220428221 is a wasteful number, since it uses less digits than its factorization.

220428221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1304335 (or 1304322 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 220428221 is about 14846.8252835413. The cubic root of 220428221 is about 604.0724999957.

The spelling of 220428221 in words is "two hundred twenty million, four hundred twenty-eight thousand, two hundred twenty-one".