666505667 has 2 divisors, whose sum is σ = 666505668. Its totient is φ = 666505666.

The previous prime is 666505657. The next prime is 666505681. The reversal of 666505667 is 766505666.

666505667 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 is a cyclic number.

It is not a de Polignac number, because 666505667 - 2²⁴ = 649728451 is a prime.

It is a super-2 number, since 2×666505667² = 888459608286229778, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (666505607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333252833 + 333252834.

It is an arithmetic number, because the mean of its divisors is an integer number (333252834).

Almost surely, 2^666505667 is an apocalyptic number.

666505667 is a deficient number, since it is larger than the sum of its proper divisors (1).

666505667 is an equidigital number, since it uses as much as digits as its factorization.

666505667 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1360800, while the sum is 47.

The square root of 666505667 is about 25816.7710413212. The cubic root of 666505667 is about 873.5101359927.

Subtracting 666505667 from its reverse (766505666), we obtain a palindrome (99999999).

The spelling of 666505667 in words is "six hundred sixty-six million, five hundred five thousand, six hundred sixty-seven".