131218 has 4 divisors (see below), whose sum is σ = 196830. Its totient is φ = 65608.

The previous prime is 131213. The next prime is 131221. The reversal of 131218 is 812131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 812131 = 113 ⋅7187.

It can be written as a sum of positive squares in only one way, i.e., 85849 + 45369 = 293^2 + 213^2 .

It is not an unprimeable number, because it can be changed into a prime (131213) by changing a digit.

131218 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32803 + ... + 32806.

2¹³¹²¹⁸ is an apocalyptic number.

131218 is a deficient number, since it is larger than the sum of its proper divisors (65612).

131218 is an equidigital number, since it uses as much as digits as its factorization.

131218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65611.

The product of its digits is 48, while the sum is 16.

The square root of 131218 is about 362.2402517667. The cubic root of 131218 is about 50.8156873865.

Adding to 131218 its reverse (812131), we get a palindrome (943349).

The spelling of 131218 in words is "one hundred thirty-one thousand, two hundred eighteen".