28715609 has 4 divisors (see below), whose sum is σ = 30924516. Its totient is φ = 26506704.

The previous prime is 28715587. The next prime is 28715627. The reversal of 28715609 is 90651782.

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 18088009 + 10627600 = 4253^2 + 3260^2 .

It is a cyclic number.

It is not a de Polignac number, because 28715609 - 2¹⁶ = 28650073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28715629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1104434 + ... + 1104459.

It is an arithmetic number, because the mean of its divisors is an integer number (7731129).

Almost surely, 2^28715609 is an apocalyptic number.

It is an amenable number.

28715609 is a deficient number, since it is larger than the sum of its proper divisors (2208907).

28715609 is a wasteful number, since it uses less digits than its factorization.

28715609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2208906.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 28715609 is about 5358.6947104682. The cubic root of 28715609 is about 306.2240836600.

The spelling of 28715609 in words is "twenty-eight million, seven hundred fifteen thousand, six hundred nine".