8139 has 4 divisors (see below), whose sum is σ = 10856. Its totient is φ = 5424.
The previous prime is 8123. The next prime is 8147. The reversal of 8139 is 9318.
It is a semiprime because it is the product of two primes.
It is not a de Polignac number, because 8139 - 24 = 8123 is a prime.
It is a D-number.
It is a Duffinian number.
8139 is a lucky number.
It is not an unprimeable number, because it can be changed into a prime (8179) 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, 1354 + ... + 1359.
It is an arithmetic number, because the mean of its divisors is an integer number (2714).
28139 is an apocalyptic number.
8139 is a deficient number, since it is larger than the sum of its proper divisors (2717).
8139 is a wasteful number, since it uses less digits than its factorization.
8139 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2716.
The product of its digits is 216, while the sum is 21.
The square root of 8139 is about 90.2164064902. The cubic root of 8139 is about 20.1151688670.
Subtracting from 8139 its sum of digits (21), we obtain a palindrome (8118).
It can be divided in two parts, 81 and 39, that added together give a triangular number (120 = T15).
The spelling of 8139 in words is "eight thousand, one hundred thirty-nine".
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