255221221 has 8 divisors (see below), whose sum is σ = 271042200. Its totient is φ = 239490048.

The previous prime is 255221209. The next prime is 255221231. The reversal of 255221221 is 122122552.

It can be written as a sum of positive squares in 4 ways, for example, as 12173121 + 243048100 = 3489^2 + 15590^2 .

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 255221221 - 2¹⁹ = 254696933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 255221192 and 255221201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255221231) 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, 16546 + ... + 28003.

It is an arithmetic number, because the mean of its divisors is an integer number (33880275).

Almost surely, 2^255221221 is an apocalyptic number.

It is an amenable number.

255221221 is a deficient number, since it is larger than the sum of its proper divisors (15820979).

255221221 is a wasteful number, since it uses less digits than its factorization.

255221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44903.

The product of its digits is 800, while the sum is 22.

The square root of 255221221 is about 15975.6446192321. The cubic root of 255221221 is about 634.3158945830.

Adding to 255221221 its reverse (122122552), we get a palindrome (377343773).

The spelling of 255221221 in words is "two hundred fifty-five million, two hundred twenty-one thousand, two hundred twenty-one".