161666717 has 2 divisors, whose sum is σ = 161666718. Its totient is φ = 161666716.

The previous prime is 161666711. The next prime is 161666777. The reversal of 161666717 is 717666161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 100420441 + 61246276 = 10021^2 + 7826^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161666717 is a prime.

It is a super-2 number, since 2×161666717² = 52272254771116178, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161666711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80833358 + 80833359.

It is an arithmetic number, because the mean of its divisors is an integer number (80833359).

Almost surely, 2^161666717 is an apocalyptic number.

It is an amenable number.

161666717 is a deficient number, since it is larger than the sum of its proper divisors (1).

161666717 is an equidigital number, since it uses as much as digits as its factorization.

161666717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504, while the sum is 41.

The square root of 161666717 is about 12714.8227278244. The cubic root of 161666717 is about 544.7620845230.

The spelling of 161666717 in words is "one hundred sixty-one million, six hundred sixty-six thousand, seven hundred seventeen".