1778318661667 has 2 divisors, whose sum is σ = 1778318661668. Its totient is φ = 1778318661666.

The previous prime is 1778318661607. The next prime is 1778318661671. The reversal of 1778318661667 is 7661668138771.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1778318661667 - 2¹¹ = 1778318659619 is a prime.

It is a super-2 number, since 2×1778318661667² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1778318661607) 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, 889159330833 + 889159330834.

It is an arithmetic number, because the mean of its divisors is an integer number (889159330834).

Almost surely, 2^{1778318661667} is an apocalyptic number.

1778318661667 is a deficient number, since it is larger than the sum of its proper divisors (1).

1778318661667 is an equidigital number, since it uses as much as digits as its factorization.

1778318661667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 85349376, while the sum is 67.

The spelling of 1778318661667 in words is "one trillion, seven hundred seventy-eight billion, three hundred eighteen million, six hundred sixty-one thousand, six hundred sixty-seven".