131778665 has 8 divisors (see below), whose sum is σ = 158380488. Its totient is φ = 105258880.

The previous prime is 131778659. The next prime is 131778701. The reversal of 131778665 is 566877131.

It can be written as a sum of positive squares in 4 ways, for example, as 27962944 + 103815721 = 5288^2 + 10189^2 .

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

It is not a de Polignac number, because 131778665 - 2⁴ = 131778649 is a prime.

It is a Duffinian number.

It is a Curzon 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, 16916 + ... + 23445.

It is an arithmetic number, because the mean of its divisors is an integer number (19797561).

Almost surely, 2^131778665 is an apocalyptic number.

It is an amenable number.

131778665 is a deficient number, since it is larger than the sum of its proper divisors (26601823).

131778665 is an equidigital number, since it uses as much as digits as its factorization.

131778665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41019.

The product of its digits is 211680, while the sum is 44.

The square root of 131778665 is about 11479.4888823501. The cubic root of 131778665 is about 508.8795921780.

The spelling of 131778665 in words is "one hundred thirty-one million, seven hundred seventy-eight thousand, six hundred sixty-five".