17666668381 has 2 divisors, whose sum is σ = 17666668382. Its totient is φ = 17666668380.

The previous prime is 17666668373. The next prime is 17666668421. The reversal of 17666668381 is 18386666671.

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., 15722652100 + 1944016281 = 125390^2 + 44091^2 .

It is an emirp because it is prime and its reverse (18386666671) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 17666668381 - 2³ = 17666668373 is a prime.

It is a super-2 number, since 2×17666668381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17666668301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8833334190 + 8833334191.

It is an arithmetic number, because the mean of its divisors is an integer number (8833334191).

Almost surely, 2^17666668381 is an apocalyptic number.

It is an amenable number.

17666668381 is a deficient number, since it is larger than the sum of its proper divisors (1).

17666668381 is an equidigital number, since it uses as much as digits as its factorization.

17666668381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 58.

The spelling of 17666668381 in words is "seventeen billion, six hundred sixty-six million, six hundred sixty-eight thousand, three hundred eighty-one".