817604666377865 has 16 divisors (see below), whose sum is σ = 999642139383888. Its totient is φ = 641739490219776.

The previous prime is 817604666377831. The next prime is 817604666377871. The reversal of 817604666377865 is 568773666406718.

It can be written as a sum of positive squares in 8 ways, for example, as 264637542723856 + 552967123654009 = 16267684^2 + 23515253^2 .

It is a cyclic number.

It is not a de Polignac number, because 817604666377865 - 2⁶ = 817604666377801 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 817604666377865.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49564967 + ... + 63967923.

It is an arithmetic number, because the mean of its divisors is an integer number (62477633711493).

Almost surely, 2^{817604666377865} is an apocalyptic number.

It is an amenable number.

817604666377865 is a deficient number, since it is larger than the sum of its proper divisors (182037473006023).

817604666377865 is a wasteful number, since it uses less digits than its factorization.

817604666377865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14617228.

The product of its (nonzero) digits is 10241925120, while the sum is 80.

The spelling of 817604666377865 in words is "eight hundred seventeen trillion, six hundred four billion, six hundred sixty-six million, three hundred seventy-seven thousand, eight hundred sixty-five".