285431221 has 2 divisors, whose sum is σ = 285431222. Its totient is φ = 285431220.

The previous prime is 285431197. The next prime is 285431233. The reversal of 285431221 is 122134582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 262764100 + 22667121 = 16210^2 + 4761^2 .

It is a cyclic number.

It is not a de Polignac number, because 285431221 - 2⁹ = 285430709 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 285431221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (285431621) 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 as a sum of consecutive naturals, namely, 142715610 + 142715611.

It is an arithmetic number, because the mean of its divisors is an integer number (142715611).

Almost surely, 2^285431221 is an apocalyptic number.

It is an amenable number.

285431221 is a deficient number, since it is larger than the sum of its proper divisors (1).

285431221 is an equidigital number, since it uses as much as digits as its factorization.

285431221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 28.

The square root of 285431221 is about 16894.7098524952. The cubic root of 285431221 is about 658.4161754996.

The spelling of 285431221 in words is "two hundred eighty-five million, four hundred thirty-one thousand, two hundred twenty-one".