17666668421 has 2 divisors, whose sum is σ = 17666668422. Its totient is φ = 17666668420.

The previous prime is 17666668381. The next prime is 17666668463. The reversal of 17666668421 is 12486666671.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11217775396 + 6448893025 = 105914^2 + 80305^2 .

It is a cyclic number.

It is not a de Polignac number, because 17666668421 - 2¹⁰ = 17666667397 is a prime.

It is a super-2 number, since 2×17666668421² (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 (17666668471) 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, 8833334210 + 8833334211.

It is an arithmetic number, because the mean of its divisors is an integer number (8833334211).

Almost surely, 2^17666668421 is an apocalyptic number.

It is an amenable number.

17666668421 is a deficient number, since it is larger than the sum of its proper divisors (1).

17666668421 is an equidigital number, since it uses as much as digits as its factorization.

17666668421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3483648, while the sum is 53.

The spelling of 17666668421 in words is "seventeen billion, six hundred sixty-six million, six hundred sixty-eight thousand, four hundred twenty-one".