13081531 has 4 divisors (see below), whose sum is σ = 13247200. Its totient is φ = 12915864.

The previous prime is 13081507. The next prime is 13081559. The reversal of 13081531 is 13518031.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13518031 = 29 ⋅466139.

It is a cyclic number.

It is not a de Polignac number, because 13081531 - 2²³ = 4692923 is a prime.

It is a super-2 number, since 2×13081531² = 342252906607922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13081591) 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, 82716 + ... + 82873.

It is an arithmetic number, because the mean of its divisors is an integer number (3311800).

Almost surely, 2^13081531 is an apocalyptic number.

13081531 is the 1618-th centered decagonal number.

13081531 is a deficient number, since it is larger than the sum of its proper divisors (165669).

13081531 is an equidigital number, since it uses as much as digits as its factorization.

13081531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165668.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 13081531 is about 3616.8399190454. The cubic root of 13081531 is about 235.6240002819.

Adding to 13081531 its reverse (13518031), we get a palindrome (26599562).

The spelling of 13081531 in words is "thirteen million, eighty-one thousand, five hundred thirty-one".