8131 has 4 divisors (see below), whose sum is σ = 8352. Its totient is φ = 7912.
The previous prime is 8123. The next prime is 8147. The reversal of 8131 is 1318.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1318 = 2 ⋅659.
It is a cyclic number.
It is not a de Polignac number, because 8131 - 23 = 8123 is a prime.
It is a super-2 number, since 2×81312 = 132226322, which contains 22 as substring.
It is a Duffinian number.
8131 is a lucky number.
It is a zygodrome in base 2.
It is not an unprimeable number, because it can be changed into a prime (8101) 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, 40 + ... + 133.
It is an arithmetic number, because the mean of its divisors is an integer number (2088).
28131 is an apocalyptic number.
8131 is a deficient number, since it is larger than the sum of its proper divisors (221).
8131 is a wasteful number, since it uses less digits than its factorization.
8131 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 220.
The product of its digits is 24, while the sum is 13.
The square root of 8131 is about 90.1720577563. The cubic root of 8131 is about 20.1085761609.
Subtracting from 8131 its sum of digits (13), we obtain a palindrome (8118).
Adding to 8131 its reverse (1318), we get a palindrome (9449).
The spelling of 8131 in words is "eight thousand, one hundred thirty-one".
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