131591605 has 8 divisors (see below), whose sum is σ = 158310072. Its totient is φ = 105006528.

The previous prime is 131591597. The next prime is 131591623. The reversal of 131591605 is 506195131.

It can be written as a sum of positive squares in 4 ways, for example, as 7447441 + 124144164 = 2729^2 + 11142^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 131591605 - 2³ = 131591597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31162 + ... + 35131.

It is an arithmetic number, because the mean of its divisors is an integer number (19788759).

Almost surely, 2^131591605 is an apocalyptic number.

It is an amenable number.

131591605 is a deficient number, since it is larger than the sum of its proper divisors (26718467).

131591605 is an equidigital number, since it uses as much as digits as its factorization.

131591605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66695.

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 131591605 is about 11471.3384136290. The cubic root of 131591605 is about 508.6386930580.

The spelling of 131591605 in words is "one hundred thirty-one million, five hundred ninety-one thousand, six hundred five".