666541607 has 2 divisors, whose sum is σ = 666541608. Its totient is φ = 666541606.

The previous prime is 666541583. The next prime is 666541663. The reversal of 666541607 is 706145666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666541607 - 2¹⁸ = 666279463 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666541697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333270803 + 333270804.

It is an arithmetic number, because the mean of its divisors is an integer number (333270804).

Almost surely, 2^666541607 is an apocalyptic number.

666541607 is a deficient number, since it is larger than the sum of its proper divisors (1).

666541607 is an equidigital number, since it uses as much as digits as its factorization.

666541607 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 41.

The square root of 666541607 is about 25817.4670910994. The cubic root of 666541607 is about 873.5258364794.

The spelling of 666541607 in words is "six hundred sixty-six million, five hundred forty-one thousand, six hundred seven".