664768 has 56 divisors (see below), whose sum is σ = 1536192. Its totient is φ = 282624.

The previous prime is 664757. The next prime is 664771. The reversal of 664768 is 867466.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14121 + ... + 14167.

It is an arithmetic number, because the mean of its divisors is an integer number (27432).

2⁶⁶⁴⁷⁶⁸ is an apocalyptic number.

664768 is a gapful number since it is divisible by the number (68) 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 664768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (768096).

664768 is an abundant number, since it is smaller than the sum of its proper divisors (871424).

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

664768 is a wasteful number, since it uses less digits than its factorization.

664768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 79 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 664768 is about 815.3330607795. Note that the first 3 decimals coincide. The cubic root of 664768 is about 87.2750357133.

The spelling of 664768 in words is "six hundred sixty-four thousand, seven hundred sixty-eight".