228391 has 4 divisors (see below), whose sum is σ = 229392. Its totient is φ = 227392.

The previous prime is 228383. The next prime is 228409. The reversal of 228391 is 193822.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 193822 = 2 ⋅96911.

It is a cyclic number.

It is not a de Polignac number, because 228391 - 2³ = 228383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30 + ... + 676.

It is an arithmetic number, because the mean of its divisors is an integer number (57348).

2²²⁸³⁹¹ is an apocalyptic number.

228391 is a deficient number, since it is larger than the sum of its proper divisors (1001).

228391 is an equidigital number, since it uses as much as digits as its factorization.

228391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000.

The product of its digits is 864, while the sum is 25.

The square root of 228391 is about 477.9027097642. The cubic root of 228391 is about 61.1260494855.

The spelling of 228391 in words is "two hundred twenty-eight thousand, three hundred ninety-one".