28508705 has 4 divisors (see below), whose sum is σ = 34210452. Its totient is φ = 22806960.

The previous prime is 28508693. The next prime is 28508713. The reversal of 28508705 is 50780582.

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 18037009 + 10471696 = 4247^2 + 3236^2 .

It is not a de Polignac number, because 28508705 - 2⁸ = 28508449 is a prime.

It is a Duffinian 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, 2850866 + ... + 2850875.

It is an arithmetic number, because the mean of its divisors is an integer number (8552613).

Almost surely, 2^28508705 is an apocalyptic number.

It is an amenable number.

28508705 is a deficient number, since it is larger than the sum of its proper divisors (5701747).

28508705 is an equidigital number, since it uses as much as digits as its factorization.

28508705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5701746.

The product of its (nonzero) digits is 22400, while the sum is 35.

The square root of 28508705 is about 5339.3543617183. The cubic root of 28508705 is about 305.4868333726.

The spelling of 28508705 in words is "twenty-eight million, five hundred eight thousand, seven hundred five".