671691 has 8 divisors (see below), whose sum is σ = 901264. Its totient is φ = 444960.

The previous prime is 671681. The next prime is 671701. The reversal of 671691 is 196176.

It is an interprime number because it is at equal distance from previous prime (671681) and next prime (671701).

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

It is not a de Polignac number, because 671691 - 2¹⁵ = 638923 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (671651) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 76 + ... + 1161.

It is an arithmetic number, because the mean of its divisors is an integer number (112658).

2⁶⁷¹⁶⁹¹ is an apocalyptic number.

671691 is a deficient number, since it is larger than the sum of its proper divisors (229573).

671691 is a wasteful number, since it uses less digits than its factorization.

671691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1421.

The product of its digits is 2268, while the sum is 30.

The square root of 671691 is about 819.5675689045. The cubic root of 671691 is about 87.5769554278.

The spelling of 671691 in words is "six hundred seventy-one thousand, six hundred ninety-one".