28117399 has 4 divisors (see below), whose sum is σ = 28771336. Its totient is φ = 27463464.

The previous prime is 28117391. The next prime is 28117409. The reversal of 28117399 is 99371182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28117399 - 2³ = 28117391 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 (28117391) 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, 326904 + ... + 326989.

It is an arithmetic number, because the mean of its divisors is an integer number (7192834).

Almost surely, 2^28117399 is an apocalyptic number.

28117399 is a deficient number, since it is larger than the sum of its proper divisors (653937).

28117399 is an equidigital number, since it uses as much as digits as its factorization.

28117399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653936.

The product of its digits is 27216, while the sum is 40.

The square root of 28117399 is about 5302.5841813214. The cubic root of 28117399 is about 304.0827012704.

The spelling of 28117399 in words is "twenty-eight million, one hundred seventeen thousand, three hundred ninety-nine".