665554478 has 4 divisors (see below), whose sum is σ = 998331720. Its totient is φ = 332777238.

The previous prime is 665554433. The next prime is 665554489. The reversal of 665554478 is 874455566.

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

It is a congruent 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 as a sum of consecutive naturals, namely, 166388618 + ... + 166388621.

It is an arithmetic number, because the mean of its divisors is an integer number (249582930).

Almost surely, 2^665554478 is an apocalyptic number.

665554478 is a deficient number, since it is larger than the sum of its proper divisors (332777242).

665554478 is a wasteful number, since it uses less digits than its factorization.

665554478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332777241.

The product of its digits is 4032000, while the sum is 50.

The square root of 665554478 is about 25798.3425436597. The cubic root of 665554478 is about 873.0944011927.

The spelling of 665554478 in words is "six hundred sixty-five million, five hundred fifty-four thousand, four hundred seventy-eight".