131511531 has 16 divisors (see below), whose sum is σ = 179118720. Its totient is φ = 85802880.

The previous prime is 131511529. The next prime is 131511557. The reversal of 131511531 is 135115131.

It is not a de Polignac number, because 131511531 - 2¹ = 131511529 is a prime.

It is a super-2 number, since 2×131511531² = 34590565571927922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 131511498 and 131511507.

It is not an unprimeable number, because it can be changed into a prime (131511581) 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, 41116 + ... + 44198.

It is an arithmetic number, because the mean of its divisors is an integer number (11194920).

Almost surely, 2^131511531 is an apocalyptic number.

131511531 is a deficient number, since it is larger than the sum of its proper divisors (47607189).

131511531 is a wasteful number, since it uses less digits than its factorization.

131511531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3386.

The product of its digits is 225, while the sum is 21.

The square root of 131511531 is about 11467.8477056508. The cubic root of 131511531 is about 508.5355025880.

Adding to 131511531 its reverse (135115131), we get a palindrome (266626662).

The spelling of 131511531 in words is "one hundred thirty-one million, five hundred eleven thousand, five hundred thirty-one".