671591 has 2 divisors, whose sum is σ = 671592. Its totient is φ = 671590.

The previous prime is 671581. The next prime is 671603. The reversal of 671591 is 195176.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671591 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671501) 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 as a sum of consecutive naturals, namely, 335795 + 335796.

It is an arithmetic number, because the mean of its divisors is an integer number (335796).

2⁶⁷¹⁵⁹¹ is an apocalyptic number.

671591 is a deficient number, since it is larger than the sum of its proper divisors (1).

671591 is an equidigital number, since it uses as much as digits as its factorization.

671591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1890, while the sum is 29.

The square root of 671591 is about 819.5065588511. The cubic root of 671591 is about 87.5726091187.

It can be divided in two parts, 6715 and 91, that multiplied together give a triangular number (611065 = T₁₁₀₅).

The spelling of 671591 in words is "six hundred seventy-one thousand, five hundred ninety-one".