645665383178 has 8 divisors (see below), whose sum is σ = 968551258980. Its totient is φ = 322814963520.

The previous prime is 645665383151. The next prime is 645665383199. The reversal of 645665383178 is 871383566546.

It can be written as a sum of positive squares in 2 ways, for example, as 615090412729 + 30574970449 = 784277^2 + 174857^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 645665383178.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8818463 + ... + 8891378.

Almost surely, 2^645665383178 is an apocalyptic number.

645665383178 is a deficient number, since it is larger than the sum of its proper divisors (322885875802).

645665383178 is a wasteful number, since it uses less digits than its factorization.

645665383178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17728072.

The product of its digits is 87091200, while the sum is 62.

The spelling of 645665383178 in words is "six hundred forty-five billion, six hundred sixty-five million, three hundred eighty-three thousand, one hundred seventy-eight".