664756 has 6 divisors (see below), whose sum is σ = 1163330. Its totient is φ = 332376.

The previous prime is 664739. The next prime is 664757. The reversal of 664756 is 657466.

It can be written as a sum of positive squares in only one way, i.e., 512656 + 152100 = 716^2 + 390^2 .

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664757) by changing a digit.

664756 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83091 + ... + 83098.

2⁶⁶⁴⁷⁵⁶ is an apocalyptic number.

It is an amenable number.

664756 is a deficient number, since it is larger than the sum of its proper divisors (498574).

664756 is a wasteful number, since it uses less digits than its factorization.

664756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166193 (or 166191 counting only the distinct ones).

The product of its digits is 30240, while the sum is 34.

The square root of 664756 is about 815.3257017904. The cubic root of 664756 is about 87.2745105644.

The spelling of 664756 in words is "six hundred sixty-four thousand, seven hundred fifty-six".