28081705 has 16 divisors (see below), whose sum is σ = 36648720. Its totient is φ = 20570112.

The previous prime is 28081681. The next prime is 28081723. The reversal of 28081705 is 50718082.

It can be written as a sum of positive squares in 8 ways, for example, as 2304 + 28079401 = 48^2 + 5299^2 .

It is a cyclic number.

It is not a de Polignac number, because 28081705 - 2⁵ = 28081673 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1320 + ... + 7609.

It is an arithmetic number, because the mean of its divisors is an integer number (2290545).

Almost surely, 2^28081705 is an apocalyptic number.

It is an amenable number.

28081705 is a deficient number, since it is larger than the sum of its proper divisors (8567015).

28081705 is a wasteful number, since it uses less digits than its factorization.

28081705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8988.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 28081705 is about 5299.2173950500. The cubic root of 28081705 is about 303.9539728619.

Adding to 28081705 its reverse (50718082), we get a palindrome (78799787).

The spelling of 28081705 in words is "twenty-eight million, eighty-one thousand, seven hundred five".