667687949786791 has 2 divisors, whose sum is σ = 667687949786792. Its totient is φ = 667687949786790.

The previous prime is 667687949786743. The next prime is 667687949786827. The reversal of 667687949786791 is 197687949786766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667687949786791 - 2¹⁷ = 667687949655719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667687949786591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333843974893395 + 333843974893396.

It is an arithmetic number, because the mean of its divisors is an integer number (333843974893396).

Almost surely, 2^{667687949786791} is an apocalyptic number.

667687949786791 is a deficient number, since it is larger than the sum of its proper divisors (1).

667687949786791 is an equidigital number, since it uses as much as digits as its factorization.

667687949786791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580717154304, while the sum is 100.

The spelling of 667687949786791 in words is "six hundred sixty-seven trillion, six hundred eighty-seven billion, nine hundred forty-nine million, seven hundred eighty-six thousand, seven hundred ninety-one".