131205817 has 4 divisors (see below), whose sum is σ = 131308276. Its totient is φ = 131103360.

The previous prime is 131205791. The next prime is 131205821. The reversal of 131205817 is 718502131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 127599616 + 3606201 = 11296^2 + 1899^2 .

It is a cyclic number.

It is not a de Polignac number, because 131205817 - 2⁷ = 131205689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131205517) 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, 49284 + ... + 51877.

It is an arithmetic number, because the mean of its divisors is an integer number (32827069).

Almost surely, 2^131205817 is an apocalyptic number.

It is an amenable number.

131205817 is a deficient number, since it is larger than the sum of its proper divisors (102459).

131205817 is a wasteful number, since it uses less digits than its factorization.

131205817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102458.

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 131205817 is about 11454.5107708710. The cubic root of 131205817 is about 508.1411466864.

Adding to 131205817 its reverse (718502131), we get a palindrome (849707948).

The spelling of 131205817 in words is "one hundred thirty-one million, two hundred five thousand, eight hundred seventeen".