131661578 has 8 divisors (see below), whose sum is σ = 202309380. Its totient is φ = 64225120.

The previous prime is 131661553. The next prime is 131661623. The reversal of 131661578 is 875166131.

It can be written as a sum of positive squares in 2 ways, for example, as 113145769 + 18515809 = 10637^2 + 4303^2 .

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

It is a super-2 number, since 2×131661578² = 34669542242900168, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 802733 + ... + 802896.

Almost surely, 2^131661578 is an apocalyptic number.

131661578 is a deficient number, since it is larger than the sum of its proper divisors (70647802).

131661578 is a wasteful number, since it uses less digits than its factorization.

131661578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1605672.

The product of its digits is 30240, while the sum is 38.

The square root of 131661578 is about 11474.3879139586. The cubic root of 131661578 is about 508.7288322142.

The spelling of 131661578 in words is "one hundred thirty-one million, six hundred sixty-one thousand, five hundred seventy-eight".