28570709 has 4 divisors (see below), whose sum is σ = 28615116. Its totient is φ = 28526304.

The previous prime is 28570673. The next prime is 28570733. The reversal of 28570709 is 90707582.

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 9891025 + 18679684 = 3145^2 + 4322^2 .

It is a cyclic number.

It is not a de Polignac number, because 28570709 - 2⁸ = 28570453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28570739) 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, 21224 + ... + 22529.

It is an arithmetic number, because the mean of its divisors is an integer number (7153779).

Almost surely, 2^28570709 is an apocalyptic number.

It is an amenable number.

28570709 is a deficient number, since it is larger than the sum of its proper divisors (44407).

28570709 is an equidigital number, since it uses as much as digits as its factorization.

28570709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44406.

The product of its (nonzero) digits is 35280, while the sum is 38.

The square root of 28570709 is about 5345.1575280809. The cubic root of 28570709 is about 305.7081422699.

The spelling of 28570709 in words is "twenty-eight million, five hundred seventy thousand, seven hundred nine".