28443231 has 10 divisors (see below), whose sum is σ = 42489392. Its totient is φ = 18962100.

The previous prime is 28443221. The next prime is 28443241. The reversal of 28443231 is 13234482.

It is an interprime number because it is at equal distance from previous prime (28443221) and next prime (28443241).

It is not a de Polignac number, because 28443231 - 2⁵ = 28443199 is a prime.

It is a super-2 number, since 2×28443231² = 1618034779438722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28443195 and 28443204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28443221) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 175495 + ... + 175656.

Almost surely, 2^28443231 is an apocalyptic number.

28443231 is a deficient number, since it is larger than the sum of its proper divisors (14046161).

28443231 is an equidigital number, since it uses as much as digits as its factorization.

28443231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351163 (or 351154 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 28443231 is about 5333.2195717034. The cubic root of 28443231 is about 305.2527905135.

The spelling of 28443231 in words is "twenty-eight million, four hundred forty-three thousand, two hundred thirty-one".