28765139 has 16 divisors (see below), whose sum is σ = 33268032. Its totient is φ = 24634368.

The previous prime is 28765097. The next prime is 28765141. The reversal of 28765139 is 93156782.

It is a cyclic number.

It is not a de Polignac number, because 28765139 - 2¹² = 28761043 is a prime.

It is a super-3 number, since 3×28765139³ (a number of 23 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28765096 and 28765105.

It is not an unprimeable number, because it can be changed into a prime (28765159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15242 + ... + 17024.

It is an arithmetic number, because the mean of its divisors is an integer number (2079252).

Almost surely, 2^28765139 is an apocalyptic number.

28765139 is a deficient number, since it is larger than the sum of its proper divisors (4502893).

28765139 is a wasteful number, since it uses less digits than its factorization.

28765139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1886.

The product of its digits is 90720, while the sum is 41.

The square root of 28765139 is about 5363.3141806163. The cubic root of 28765139 is about 306.4000456465.

The spelling of 28765139 in words is "twenty-eight million, seven hundred sixty-five thousand, one hundred thirty-nine".