228840391 has 4 divisors (see below), whose sum is σ = 246443512. Its totient is φ = 211237272.

The previous prime is 228840373. The next prime is 228840431. The reversal of 228840391 is 193048822.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193048822 = 2 ⋅96524411.

It is a cyclic number.

It is not a de Polignac number, because 228840391 - 2⁷ = 228840263 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 228840391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228840361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8801541 + ... + 8801566.

It is an arithmetic number, because the mean of its divisors is an integer number (61610878).

Almost surely, 2^228840391 is an apocalyptic number.

228840391 is a deficient number, since it is larger than the sum of its proper divisors (17603121).

228840391 is a wasteful number, since it uses less digits than its factorization.

228840391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17603120.

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 228840391 is about 15127.4714013942. The cubic root of 228840391 is about 611.6611454863.

The spelling of 228840391 in words is "two hundred twenty-eight million, eight hundred forty thousand, three hundred ninety-one".