664740 has 48 divisors (see below), whose sum is σ = 2069760. Its totient is φ = 177120.

The previous prime is 664739. The next prime is 664757. The reversal of 664740 is 47466.

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

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 664740.

It is an unprimeable 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 15 ways as a sum of consecutive naturals, for example, 76 + ... + 1155.

It is an arithmetic number, because the mean of its divisors is an integer number (43120).

2⁶⁶⁴⁷⁴⁰ is an apocalyptic number.

664740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1034880).

664740 is an abundant number, since it is smaller than the sum of its proper divisors (1405020).

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

664740 is a wasteful number, since it uses less digits than its factorization.

664740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1249 (or 1241 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 664740 is about 815.3158897017. The cubic root of 664740 is about 87.2738103559.

It can be divided in two parts, 6 and 64740, that added together give a palindrome (64746).

The spelling of 664740 in words is "six hundred sixty-four thousand, seven hundred forty".