131605291 has 4 divisors (see below), whose sum is σ = 132094800. Its totient is φ = 131115784.

The previous prime is 131605249. The next prime is 131605297. The reversal of 131605291 is 192506131.

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

It is a cyclic number.

It is not a de Polignac number, because 131605291 - 2¹⁹ = 131081003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131605297) 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, 244351 + ... + 244888.

It is an arithmetic number, because the mean of its divisors is an integer number (33023700).

Almost surely, 2^131605291 is an apocalyptic number.

131605291 is a deficient number, since it is larger than the sum of its proper divisors (489509).

131605291 is an equidigital number, since it uses as much as digits as its factorization.

131605291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489508.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 131605291 is about 11471.9349283371. The cubic root of 131605291 is about 508.6563258642.

The spelling of 131605291 in words is "one hundred thirty-one million, six hundred five thousand, two hundred ninety-one".