28509799 has 4 divisors (see below), whose sum is σ = 30186864. Its totient is φ = 26832736.

The previous prime is 28509797. The next prime is 28509827. The reversal of 28509799 is 99790582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99790582 = 2 ⋅49895291.

It is a cyclic number.

It is not a de Polignac number, because 28509799 - 2¹ = 28509797 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 (28509791) 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, 838507 + ... + 838540.

It is an arithmetic number, because the mean of its divisors is an integer number (7546716).

Almost surely, 2^28509799 is an apocalyptic number.

28509799 is a deficient number, since it is larger than the sum of its proper divisors (1677065).

28509799 is a wasteful number, since it uses less digits than its factorization.

28509799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1677064.

The product of its (nonzero) digits is 408240, while the sum is 49.

The square root of 28509799 is about 5339.4568075788. The cubic root of 28509799 is about 305.4907409314.

The spelling of 28509799 in words is "twenty-eight million, five hundred nine thousand, seven hundred ninety-nine".