28278605 has 4 divisors (see below), whose sum is σ = 33934332. Its totient is φ = 22622880.

The previous prime is 28278587. The next prime is 28278617. The reversal of 28278605 is 50687282.

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 3736489 + 24542116 = 1933^2 + 4954^2 .

It is not a de Polignac number, because 28278605 - 2¹² = 28274509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2827856 + ... + 2827865.

It is an arithmetic number, because the mean of its divisors is an integer number (8483583).

Almost surely, 2^28278605 is an apocalyptic number.

It is an amenable number.

28278605 is a deficient number, since it is larger than the sum of its proper divisors (5655727).

28278605 is an equidigital number, since it uses as much as digits as its factorization.

28278605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5655726.

The product of its (nonzero) digits is 53760, while the sum is 38.

The square root of 28278605 is about 5317.7631575692. The cubic root of 28278605 is about 304.6627284967.

It can be divided in two parts, 282 and 78605, that added together give a palindrome (78887).

The spelling of 28278605 in words is "twenty-eight million, two hundred seventy-eight thousand, six hundred five".