131609281 has 4 divisors (see below), whose sum is σ = 132614064. Its totient is φ = 130604500.

The previous prime is 131609273. The next prime is 131609293. The reversal of 131609281 is 182906131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 182906131 = 12457 ⋅14683.

It is a cyclic number.

It is not a de Polignac number, because 131609281 - 2³ = 131609273 is a prime.

It is a super-2 number, since 2×131609281² = 34642005690673922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131609081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 502195 + ... + 502456.

It is an arithmetic number, because the mean of its divisors is an integer number (33153516).

Almost surely, 2^131609281 is an apocalyptic number.

It is an amenable number.

131609281 is a deficient number, since it is larger than the sum of its proper divisors (1004783).

131609281 is a wasteful number, since it uses less digits than its factorization.

131609281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1004782.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 131609281 is about 11472.1088296790. The cubic root of 131609281 is about 508.6614662813.

The spelling of 131609281 in words is "one hundred thirty-one million, six hundred nine thousand, two hundred eighty-one".