666171634 has 4 divisors (see below), whose sum is σ = 999257454. Its totient is φ = 333085816.

The previous prime is 666171601. The next prime is 666171661. The reversal of 666171634 is 436171666.

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

It can be written as a sum of positive squares in only one way, i.e., 625250025 + 40921609 = 25005^2 + 6397^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166542907 + ... + 166542910.

Almost surely, 2^666171634 is an apocalyptic number.

666171634 is a deficient number, since it is larger than the sum of its proper divisors (333085820).

666171634 is a wasteful number, since it uses less digits than its factorization.

666171634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333085819.

The product of its digits is 108864, while the sum is 40.

The square root of 666171634 is about 25810.3009281178. The cubic root of 666171634 is about 873.3641857614.

The spelling of 666171634 in words is "six hundred sixty-six million, one hundred seventy-one thousand, six hundred thirty-four".