131206505 has 4 divisors (see below), whose sum is σ = 157447812. Its totient is φ = 104965200.

The previous prime is 131206489. The next prime is 131206507. The reversal of 131206505 is 505602131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 505602131 = 1063 ⋅475637.

It can be written as a sum of positive squares in 2 ways, for example, as 76090729 + 55115776 = 8723^2 + 7424^2 .

It is not a de Polignac number, because 131206505 - 2⁴ = 131206489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131206507) 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, 13120646 + ... + 13120655.

It is an arithmetic number, because the mean of its divisors is an integer number (39361953).

Almost surely, 2^131206505 is an apocalyptic number.

It is an amenable number.

131206505 is a deficient number, since it is larger than the sum of its proper divisors (26241307).

131206505 is an equidigital number, since it uses as much as digits as its factorization.

131206505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26241306.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 131206505 is about 11454.5408026686. The cubic root of 131206505 is about 508.1420348597.

Adding to 131206505 its reverse (505602131), we get a palindrome (636808636).

The spelling of 131206505 in words is "one hundred thirty-one million, two hundred six thousand, five hundred five".