664605 has 24 divisors (see below), whose sum is σ = 1196832. Its totient is φ = 353808.

The previous prime is 664603. The next prime is 664613. The reversal of 664605 is 506466.

It is not a de Polignac number, because 664605 - 2¹ = 664603 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664603) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 942 + ... + 1488.

It is an arithmetic number, because the mean of its divisors is an integer number (49868).

2⁶⁶⁴⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

664605 is a deficient number, since it is larger than the sum of its proper divisors (532227).

664605 is an equidigital number, since it uses as much as digits as its factorization.

664605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567 (or 555 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 664605 is about 815.2330955009. The cubic root of 664605 is about 87.2679018994.

The spelling of 664605 in words is "six hundred sixty-four thousand, six hundred five".