17666653661 has 2 divisors, whose sum is σ = 17666653662. Its totient is φ = 17666653660.

The previous prime is 17666653607. The next prime is 17666653681. The reversal of 17666653661 is 16635666671.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8925525625 + 8741128036 = 94475^2 + 93494^2 .

It is a cyclic number.

It is not a de Polignac number, because 17666653661 - 2¹⁴ = 17666637277 is a prime.

It is a super-2 number, since 2×17666653661² (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 (17666653681) 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, 8833326830 + 8833326831.

It is an arithmetic number, because the mean of its divisors is an integer number (8833326831).

Almost surely, 2^17666653661 is an apocalyptic number.

It is an amenable number.

17666653661 is a deficient number, since it is larger than the sum of its proper divisors (1).

17666653661 is an equidigital number, since it uses as much as digits as its factorization.

17666653661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4898880, while the sum is 53.

The spelling of 17666653661 in words is "seventeen billion, six hundred sixty-six million, six hundred fifty-three thousand, six hundred sixty-one".