671985 has 24 divisors (see below), whose sum is σ = 1184040. Its totient is φ = 352512.

The previous prime is 671981. The next prime is 671999. The reversal of 671985 is 589176.

It can be written as a sum of positive squares in 4 ways, for example, as 136161 + 535824 = 369^2 + 732^2 .

It is not a de Polignac number, because 671985 - 2² = 671981 is a prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 671985.

It is not an unprimeable number, because it can be changed into a prime (671981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4837 + ... + 4973.

It is an arithmetic number, because the mean of its divisors is an integer number (49335).

2⁶⁷¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

671985 is a deficient number, since it is larger than the sum of its proper divisors (512055).

671985 is a wasteful number, since it uses less digits than its factorization.

671985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 254 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 671985 is about 819.7469121625. The cubic root of 671985 is about 87.5897310788.

The spelling of 671985 in words is "six hundred seventy-one thousand, nine hundred eighty-five".