1668516851669 has 2 divisors, whose sum is σ = 1668516851670. Its totient is φ = 1668516851668.

The previous prime is 1668516851663. The next prime is 1668516851707. The reversal of 1668516851669 is 9661586158661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 946164744100 + 722352107569 = 972710^2 + 849913^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668516851669 is a prime.

It is a super-2 number, since 2×1668516851669² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1668516851599 and 1668516851608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668516851663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834258425834 + 834258425835.

It is an arithmetic number, because the mean of its divisors is an integer number (834258425835).

Almost surely, 2^{1668516851669} is an apocalyptic number.

It is an amenable number.

1668516851669 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668516851669 is an equidigital number, since it uses as much as digits as its factorization.

1668516851669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 111974400, while the sum is 68.

The spelling of 1668516851669 in words is "one trillion, six hundred sixty-eight billion, five hundred sixteen million, eight hundred fifty-one thousand, six hundred sixty-nine".