20131 has 4 divisors (see below), whose sum is σ = 20664.
Its totient is φ = 19600.
The previous prime is 20129. The next prime is 20143. The reversal of 20131 is 13102.
20131 is nontrivially palindromic in base 11.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13102 = 2 ⋅6551.
It is a cyclic number.
It is not a de Polignac number, because 20131 - 21 = 20129 is a prime.
It is a super-2 number, since 2×201312 = 810514322, which contains 22 as substring.
20131 is an undulating number in base 11.
It is a plaindrome in base 7.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20101) 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, 205 + ... + 286.
It is an arithmetic number, because the mean of its divisors is an integer number (5166).
220131 is an apocalyptic number.
20131 is a deficient number, since it is larger than the sum of its proper divisors (533).
20131 is an equidigital number, since it uses as much as digits as its factorization.
20131 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 532.
The product of its (nonzero) digits is 6, while the sum is 7.
The square root of 20131 is about 141.8837552365.
The cubic root of 20131 is about 27.2033120246.
Adding to 20131 its reverse (13102), we get a palindrome (33233).
It can be divided in two parts, 201 and 31, that added together give a palindrome (232).
The spelling of 20131 in words is "twenty thousand, one hundred thirty-one".