671891 has 8 divisors (see below), whose sum is σ = 776304. Its totient is φ = 574720.

The previous prime is 671887. The next prime is 671893. The reversal of 671891 is 198176.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 671891 - 2² = 671887 is a prime.

It is a Duffinian number.

It is a plaindrome in base 6.

It is not an unprimeable number, because it can be changed into a prime (671893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1610 + ... + 1983.

It is an arithmetic number, because the mean of its divisors is an integer number (97038).

2⁶⁷¹⁸⁹¹ is an apocalyptic number.

671891 is a deficient number, since it is larger than the sum of its proper divisors (104413).

671891 is a wasteful number, since it uses less digits than its factorization.

671891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3621.

The product of its digits is 3024, while the sum is 32.

The square root of 671891 is about 819.6895753881. The cubic root of 671891 is about 87.5856467521.

Multiplying 671891 by its sum of digits (32), we get a palindrome (21500512).

The spelling of 671891 in words is "six hundred seventy-one thousand, eight hundred ninety-one".