28583281 has 4 divisors (see below), whose sum is σ = 28878052. Its totient is φ = 28288512.

The previous prime is 28583207. The next prime is 28583287. The reversal of 28583281 is 18238582.

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 7789681 + 20793600 = 2791^2 + 4560^2 .

It is a cyclic number.

It is not a de Polignac number, because 28583281 - 2⁷ = 28583153 is a prime.

It is a super-2 number, since 2×28583281² = 1634007905449922, which contains 22 as substring.

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 28583281.

It is not an unprimeable number, because it can be changed into a prime (28583287) 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, 147240 + ... + 147433.

It is an arithmetic number, because the mean of its divisors is an integer number (7219513).

Almost surely, 2^28583281 is an apocalyptic number.

It is an amenable number.

28583281 is a deficient number, since it is larger than the sum of its proper divisors (294771).

28583281 is an equidigital number, since it uses as much as digits as its factorization.

28583281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294770.

The product of its digits is 30720, while the sum is 37.

The square root of 28583281 is about 5346.3334164640. Note that the first 3 decimals coincide. The cubic root of 28583281 is about 305.7529760560.

The spelling of 28583281 in words is "twenty-eight million, five hundred eighty-three thousand, two hundred eighty-one".