166909 has 2 divisors, whose sum is σ = 166910. Its totient is φ = 166908.

The previous prime is 166871. The next prime is 166919. The reversal of 166909 is 909661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142884 + 24025 = 378^2 + 155^2 .

It is a cyclic number.

It is not a de Polignac number, because 166909 - 2⁷ = 166781 is a prime.

It is a super-2 number, since 2×166909² = 55717228562, which contains 22 as substring.

166909 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83454 + 83455.

It is an arithmetic number, because the mean of its divisors is an integer number (83455).

2¹⁶⁶⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

166909 is a deficient number, since it is larger than the sum of its proper divisors (1).

166909 is an equidigital number, since it uses as much as digits as its factorization.

166909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 166909 is about 408.5449791639. The cubic root of 166909 is about 55.0587801328.

The spelling of 166909 in words is "one hundred sixty-six thousand, nine hundred nine".