131131221 has 16 divisors (see below), whose sum is σ = 188497344. Its totient is φ = 80607744.

The previous prime is 131131199. The next prime is 131131279. The reversal of 131131221 is 122131131.

It is a happy number.

It is not a de Polignac number, because 131131221 - 2⁹ = 131130709 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 131131221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131131291) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64005 + ... + 66021.

It is an arithmetic number, because the mean of its divisors is an integer number (11781084).

Almost surely, 2^131131221 is an apocalyptic number.

It is an amenable number.

131131221 is a deficient number, since it is larger than the sum of its proper divisors (57366123).

131131221 is a wasteful number, since it uses less digits than its factorization.

131131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3700.

The product of its digits is 36, while the sum is 15.

The square root of 131131221 is about 11451.2541234574. The cubic root of 131131221 is about 508.0448285920.

Adding to 131131221 its reverse (122131131), we get a palindrome (253262352).

The spelling of 131131221 in words is "one hundred thirty-one million, one hundred thirty-one thousand, two hundred twenty-one".