664340 has 24 divisors (see below), whose sum is σ = 1421280. Its totient is φ = 260768.

The previous prime is 664331. The next prime is 664357. The reversal of 664340 is 43466.

664340 is an esthetic number in base 7, because in such base its adjacent digits differ by 1.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664340.

It is an unprimeable number.

664340 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 899 + ... + 1461.

It is an arithmetic number, because the mean of its divisors is an integer number (59220).

2⁶⁶⁴³⁴⁰ is an apocalyptic number.

It is an amenable number.

664340 is an abundant number, since it is smaller than the sum of its proper divisors (756940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664340 is a wasteful number, since it uses less digits than its factorization.

664340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631 (or 629 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 664340 is about 815.0705490938. The cubic root of 664340 is about 87.2563014909.

It can be divided in two parts, 6 and 64340, that added together give a palindrome (64346).

The spelling of 664340 in words is "six hundred sixty-four thousand, three hundred forty".