817660685 has 4 divisors (see below), whose sum is σ = 981192828. Its totient is φ = 654128544.

The previous prime is 817660667. The next prime is 817660693. The reversal of 817660685 is 586066718.

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

It can be written as a sum of positive squares in 2 ways, for example, as 410710756 + 406949929 = 20266^2 + 20173^2 .

It is a cyclic number.

It is not a de Polignac number, because 817660685 - 2¹⁴ = 817644301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81766064 + ... + 81766073.

It is an arithmetic number, because the mean of its divisors is an integer number (245298207).

Almost surely, 2^817660685 is an apocalyptic number.

It is an amenable number.

817660685 is a deficient number, since it is larger than the sum of its proper divisors (163532143).

817660685 is a wasteful number, since it uses less digits than its factorization.

817660685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163532142.

The product of its (nonzero) digits is 483840, while the sum is 47.

The square root of 817660685 is about 28594.7667414861. The cubic root of 817660685 is about 935.0992430904.

The spelling of 817660685 in words is "eight hundred seventeen million, six hundred sixty thousand, six hundred eighty-five".