663949875065 has 4 divisors (see below), whose sum is σ = 796739850084. Its totient is φ = 531159900048.

The previous prime is 663949875059. The next prime is 663949875097. The reversal of 663949875065 is 560578949366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 560578949366 = 2 ⋅280289474683.

It can be written as a sum of positive squares in 2 ways, for example, as 479822206864 + 184127668201 = 692692^2 + 429101^2 .

It is a cyclic number.

It is not a de Polignac number, because 663949875065 - 2¹⁴ = 663949858681 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 663949874986 and 663949875004.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66394987502 + ... + 66394987511.

It is an arithmetic number, because the mean of its divisors is an integer number (199184962521).

Almost surely, 2^663949875065 is an apocalyptic number.

It is an amenable number.

663949875065 is a deficient number, since it is larger than the sum of its proper divisors (132789975019).

663949875065 is a wasteful number, since it uses less digits than its factorization.

663949875065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132789975018.

The product of its (nonzero) digits is 293932800, while the sum is 68.

The spelling of 663949875065 in words is "six hundred sixty-three billion, nine hundred forty-nine million, eight hundred seventy-five thousand, sixty-five".