671989 has 4 divisors (see below), whose sum is σ = 673740. Its totient is φ = 670240.

The previous prime is 671981. The next prime is 671999. The reversal of 671989 is 989176.

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 378225 + 293764 = 615^2 + 542^2 .

It is a cyclic number.

It is not a de Polignac number, because 671989 - 2³ = 671981 is a prime.

It is a super-2 number, since 2×671989² = 903138432242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 22 + ... + 1159.

It is an arithmetic number, because the mean of its divisors is an integer number (168435).

2⁶⁷¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

671989 is a deficient number, since it is larger than the sum of its proper divisors (1751).

671989 is a wasteful number, since it uses less digits than its factorization.

671989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1750.

The product of its digits is 27216, while the sum is 40.

The square root of 671989 is about 819.7493519363. The cubic root of 671989 is about 87.5899048714.

The spelling of 671989 in words is "six hundred seventy-one thousand, nine hundred eighty-nine".