28391879 has 4 divisors (see below), whose sum is σ = 28403184. Its totient is φ = 28380576.

The previous prime is 28391873. The next prime is 28391897. The reversal of 28391879 is 97819382.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 97819382 = 2 ⋅48909691.

It is a cyclic number.

It is not a de Polignac number, because 28391879 - 2²⁴ = 11614663 is a prime.

It is a super-3 number, since 3×28391879³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28391873) 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, 2 + ... + 7535.

It is an arithmetic number, because the mean of its divisors is an integer number (7100796).

Almost surely, 2^28391879 is an apocalyptic number.

28391879 is a deficient number, since it is larger than the sum of its proper divisors (11305).

28391879 is an equidigital number, since it uses as much as digits as its factorization.

28391879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11304.

The product of its digits is 217728, while the sum is 47.

The square root of 28391879 is about 5328.4030440649. The cubic root of 28391879 is about 305.0689766060.

The spelling of 28391879 in words is "twenty-eight million, three hundred ninety-one thousand, eight hundred seventy-nine".