665677871 has 4 divisors (see below), whose sum is σ = 665858352. Its totient is φ = 665497392.

The previous prime is 665677847. The next prime is 665677879. The reversal of 665677871 is 178776566.

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

It is a cyclic number.

It is not a de Polignac number, because 665677871 - 2¹⁸ = 665415727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665677879) 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, 84590 + ... + 92123.

It is an arithmetic number, because the mean of its divisors is an integer number (166464588).

Almost surely, 2^665677871 is an apocalyptic number.

665677871 is a deficient number, since it is larger than the sum of its proper divisors (180481).

665677871 is a wasteful number, since it uses less digits than its factorization.

665677871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180480.

The product of its digits is 2963520, while the sum is 53.

The square root of 665677871 is about 25800.7339236697. The cubic root of 665677871 is about 873.1483547426.

The spelling of 665677871 in words is "six hundred sixty-five million, six hundred seventy-seven thousand, eight hundred seventy-one".