28143289 has 4 divisors (see below), whose sum is σ = 28433524. Its totient is φ = 27853056.

The previous prime is 28143287. The next prime is 28143307. The reversal of 28143289 is 98234182.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5978025 + 22165264 = 2445^2 + 4708^2 .

It is a cyclic number.

It is not a de Polignac number, because 28143289 - 2¹ = 28143287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28143281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144972 + ... + 145165.

It is an arithmetic number, because the mean of its divisors is an integer number (7108381).

Almost surely, 2^28143289 is an apocalyptic number.

It is an amenable number.

28143289 is a deficient number, since it is larger than the sum of its proper divisors (290235).

28143289 is an equidigital number, since it uses as much as digits as its factorization.

28143289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290234.

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

The square root of 28143289 is about 5305.0248821283. The cubic root of 28143289 is about 304.1760039501.

The spelling of 28143289 in words is "twenty-eight million, one hundred forty-three thousand, two hundred eighty-nine".