664949 has 2 divisors, whose sum is σ = 664950. Its totient is φ = 664948.

The previous prime is 664933. The next prime is 664967. The reversal of 664949 is 949466.

664949 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 628849 + 36100 = 793^2 + 190^2 .

It is a cyclic number.

It is not a de Polignac number, because 664949 - 2⁴ = 664933 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332474 + 332475.

It is an arithmetic number, because the mean of its divisors is an integer number (332475).

2⁶⁶⁴⁹⁴⁹ is an apocalyptic number.

It is an amenable number.

664949 is a deficient number, since it is larger than the sum of its proper divisors (1).

664949 is an equidigital number, since it uses as much as digits as its factorization.

664949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 38.

The square root of 664949 is about 815.4440508091. Note that the first 3 decimals coincide. The cubic root of 664949 is about 87.2829559442.

The spelling of 664949 in words is "six hundred sixty-four thousand, nine hundred forty-nine".