667168591 has 2 divisors, whose sum is σ = 667168592. Its totient is φ = 667168590.

The previous prime is 667168589. The next prime is 667168597. The reversal of 667168591 is 195861766.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 667168591 - 2¹ = 667168589 is a prime.

It is a super-2 number, since 2×667168591² = 890227857633850562, which contains 22 as substring.

Together with 667168589, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667168597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333584295 + 333584296.

It is an arithmetic number, because the mean of its divisors is an integer number (333584296).

Almost surely, 2^667168591 is an apocalyptic number.

667168591 is a deficient number, since it is larger than the sum of its proper divisors (1).

667168591 is an equidigital number, since it uses as much as digits as its factorization.

667168591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 49.

The square root of 667168591 is about 25829.6068688627. The cubic root of 667168591 is about 873.7996453856.

The spelling of 667168591 in words is "six hundred sixty-seven million, one hundred sixty-eight thousand, five hundred ninety-one".