166864209 has 16 divisors (see below), whose sum is σ = 229006272. Its totient is φ = 108013248.

The previous prime is 166864207. The next prime is 166864249. The reversal of 166864209 is 902468661.

It is not a de Polignac number, because 166864209 - 2¹ = 166864207 is a prime.

It is a super-3 number, since 3×166864209³ (a number of 26 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (166864207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18579 + ... + 26055.

It is an arithmetic number, because the mean of its divisors is an integer number (14312892).

Almost surely, 2^166864209 is an apocalyptic number.

It is an amenable number.

166864209 is a deficient number, since it is larger than the sum of its proper divisors (62142063).

166864209 is a wasteful number, since it uses less digits than its factorization.

166864209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7696.

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 166864209 is about 12917.5930033424. The cubic root of 166864209 is about 550.5385457760.

The spelling of 166864209 in words is "one hundred sixty-six million, eight hundred sixty-four thousand, two hundred nine".