664777 has 2 divisors, whose sum is σ = 664778. Its totient is φ = 664776.

The previous prime is 664771. The next prime is 664789. The reversal of 664777 is 777466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 657721 + 7056 = 811^2 + 84^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664777 is a prime.

It is not a weakly prime, because it can be changed into another prime (664771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332388 + 332389.

It is an arithmetic number, because the mean of its divisors is an integer number (332389).

2⁶⁶⁴⁷⁷⁷ is an apocalyptic number.

It is an amenable number.

664777 is a deficient number, since it is larger than the sum of its proper divisors (1).

664777 is an equidigital number, since it uses as much as digits as its factorization.

664777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49392, while the sum is 37.

The square root of 664777 is about 815.3385799777. The cubic root of 664777 is about 87.2754295709.

It can be divided in two parts, 6647 and 77, that added together give a square (6724 = 82²).

The spelling of 664777 in words is "six hundred sixty-four thousand, seven hundred seventy-seven".