16668181669 has 2 divisors, whose sum is σ = 16668181670. Its totient is φ = 16668181668.

The previous prime is 16668181667. The next prime is 16668181687. The reversal of 16668181669 is 96618186661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15622500100 + 1045681569 = 124990^2 + 32337^2 .

It is a cyclic number.

It is not a de Polignac number, because 16668181669 - 2¹ = 16668181667 is a prime.

It is a super-2 number, since 2×16668181669² (a number of 21 digits) contains 22 as substring.

Together with 16668181667, 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 (16668181667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8334090834 + 8334090835.

It is an arithmetic number, because the mean of its divisors is an integer number (8334090835).

Almost surely, 2^16668181669 is an apocalyptic number.

It is an amenable number.

16668181669 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668181669 is an equidigital number, since it uses as much as digits as its factorization.

16668181669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4478976, while the sum is 58.

The spelling of 16668181669 in words is "sixteen billion, six hundred sixty-eight million, one hundred eighty-one thousand, six hundred sixty-nine".