28678281 has 4 divisors (see below), whose sum is σ = 38237712. Its totient is φ = 19118852.

The previous prime is 28678271. The next prime is 28678283. The reversal of 28678281 is 18287682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28678281 - 2¹⁸ = 28416137 is a prime.

It is a super-2 number, since 2×28678281² = 1644887602229922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28678283) 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, 4779711 + ... + 4779716.

It is an arithmetic number, because the mean of its divisors is an integer number (9559428).

Almost surely, 2^28678281 is an apocalyptic number.

It is an amenable number.

28678281 is a deficient number, since it is larger than the sum of its proper divisors (9559431).

28678281 is an equidigital number, since it uses as much as digits as its factorization.

28678281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9559430.

The product of its digits is 86016, while the sum is 42.

The square root of 28678281 is about 5355.2106401149. The cubic root of 28678281 is about 306.0913371668.

The spelling of 28678281 in words is "twenty-eight million, six hundred seventy-eight thousand, two hundred eighty-one".