663671 has 4 divisors (see below), whose sum is σ = 670344. Its totient is φ = 657000.

The previous prime is 663661. The next prime is 663683. The reversal of 663671 is 176366.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 663671 - 2¹⁰ = 662647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663601) 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, 3185 + ... + 3386.

It is an arithmetic number, because the mean of its divisors is an integer number (167586).

2⁶⁶³⁶⁷¹ is an apocalyptic number.

663671 is a deficient number, since it is larger than the sum of its proper divisors (6673).

663671 is a wasteful number, since it uses less digits than its factorization.

663671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6672.

The product of its digits is 4536, while the sum is 29.

The square root of 663671 is about 814.6600518007. The cubic root of 663671 is about 87.2270022008.

The spelling of 663671 in words is "six hundred sixty-three thousand, six hundred seventy-one".