664171 has 8 divisors (see below), whose sum is σ = 705024. Its totient is φ = 624360.

The previous prime is 664151. The next prime is 664177. The reversal of 664171 is 171466.

It is a happy number.

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 664171 - 2⁷ = 664043 is a prime.

It is a super-2 number, since 2×664171² = 882246234482, which contains 22 as substring.

It is a Duffinian number.

664171 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (664177) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1326 + ... + 1756.

It is an arithmetic number, because the mean of its divisors is an integer number (88128).

2⁶⁶⁴¹⁷¹ is an apocalyptic number.

664171 is a deficient number, since it is larger than the sum of its proper divisors (40853).

664171 is a wasteful number, since it uses less digits than its factorization.

664171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521.

The product of its digits is 1008, while the sum is 25.

The square root of 664171 is about 814.9668704923. The cubic root of 664171 is about 87.2489018835.

The spelling of 664171 in words is "six hundred sixty-four thousand, one hundred seventy-one".