671785 has 16 divisors (see below), whose sum is σ = 861840. Its totient is φ = 501760.

The previous prime is 671779. The next prime is 671791. The reversal of 671785 is 587176.

It is an interprime number because it is at equal distance from previous prime (671779) and next prime (671791).

It can be written as a sum of positive squares in 8 ways, for example, as 257049 + 414736 = 507^2 + 644^2 .

It is not a de Polignac number, because 671785 - 2³ = 671777 is a prime.

671785 is a lucky number.

It is a plaindrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 671785.

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, 5889 + ... + 6001.

It is an arithmetic number, because the mean of its divisors is an integer number (53865).

2⁶⁷¹⁷⁸⁵ is an apocalyptic number.

It is an amenable number.

671785 is a deficient number, since it is larger than the sum of its proper divisors (190055).

671785 is a wasteful number, since it uses less digits than its factorization.

671785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188.

The product of its digits is 11760, while the sum is 34.

The square root of 671785 is about 819.6249142138. The cubic root of 671785 is about 87.5810405651.

The spelling of 671785 in words is "six hundred seventy-one thousand, seven hundred eighty-five".