665157187 has 4 divisors (see below), whose sum is σ = 700165480. Its totient is φ = 630148896.

The previous prime is 665157179. The next prime is 665157193. The reversal of 665157187 is 781751566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 781751566 = 2 ⋅390875783.

It is a cyclic number.

It is not a de Polignac number, because 665157187 - 2³ = 665157179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665157287) by changing a digit.

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, 17504118 + ... + 17504155.

It is an arithmetic number, because the mean of its divisors is an integer number (175041370).

Almost surely, 2^665157187 is an apocalyptic number.

665157187 is a deficient number, since it is larger than the sum of its proper divisors (35008293).

665157187 is a wasteful number, since it uses less digits than its factorization.

665157187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35008292.

The product of its digits is 352800, while the sum is 46.

The square root of 665157187 is about 25790.6414615845. The cubic root of 665157187 is about 872.9206405155.

The spelling of 665157187 in words is "six hundred sixty-five million, one hundred fifty-seven thousand, one hundred eighty-seven".