667649 has 2 divisors, whose sum is σ = 667650. Its totient is φ = 667648.

The previous prime is 667643. The next prime is 667657. The reversal of 667649 is 946766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 552049 + 115600 = 743^2 + 340^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (667643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333824 + 333825.

It is an arithmetic number, because the mean of its divisors is an integer number (333825).

It is a Proth number, since it is equal to 163 ⋅ 2¹² + 1 and 163 < 2¹².

2⁶⁶⁷⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

667649 is a deficient number, since it is larger than the sum of its proper divisors (1).

667649 is an equidigital number, since it uses as much as digits as its factorization.

667649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 38.

The square root of 667649 is about 817.0979133494. The cubic root of 667649 is about 87.4009327767.

The spelling of 667649 in words is "six hundred sixty-seven thousand, six hundred forty-nine".