667643 has 2 divisors, whose sum is σ = 667644. Its totient is φ = 667642.

The previous prime is 667631. The next prime is 667649. The reversal of 667643 is 346766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667643 - 2¹² = 663547 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (667649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333821 + 333822.

It is an arithmetic number, because the mean of its divisors is an integer number (333822).

2⁶⁶⁷⁶⁴³ is an apocalyptic number.

667643 is a deficient number, since it is larger than the sum of its proper divisors (1).

667643 is an equidigital number, since it uses as much as digits as its factorization.

667643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 32.

The square root of 667643 is about 817.0942418106. The cubic root of 667643 is about 87.4006709589.

The spelling of 667643 in words is "six hundred sixty-seven thousand, six hundred forty-three".