166601689 has 2 divisors, whose sum is σ = 166601690. Its totient is φ = 166601688.

The previous prime is 166601623. The next prime is 166601707. The reversal of 166601689 is 986106661.

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., 146216464 + 20385225 = 12092^2 + 4515^2 .

It is an emirp because it is prime and its reverse (986106661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166601689 - 2²¹ = 164504537 is a prime.

It is a super-2 number, since 2×166601689² = 55512245555305442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (166601609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83300844 + 83300845.

It is an arithmetic number, because the mean of its divisors is an integer number (83300845).

Almost surely, 2^166601689 is an apocalyptic number.

It is an amenable number.

166601689 is a deficient number, since it is larger than the sum of its proper divisors (1).

166601689 is an equidigital number, since it uses as much as digits as its factorization.

166601689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 166601689 is about 12907.4276678198. The cubic root of 166601689 is about 550.2496816770.

The spelling of 166601689 in words is "one hundred sixty-six million, six hundred one thousand, six hundred eighty-nine".