166959991 has 8 divisors (see below), whose sum is σ = 182246400. Its totient is φ = 151691640.

The previous prime is 166959983. The next prime is 166960019. The reversal of 166959991 is 199959661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166959991 - 2³ = 166959983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166959901) 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 in 7 ways as a sum of consecutive naturals, for example, 21240 + ... + 28018.

It is an arithmetic number, because the mean of its divisors is an integer number (22780800).

Almost surely, 2^166959991 is an apocalyptic number.

166959991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166959991 is a deficient number, since it is larger than the sum of its proper divisors (15286409).

166959991 is a wasteful number, since it uses less digits than its factorization.

166959991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9029.

The product of its digits is 1180980, while the sum is 55.

The square root of 166959991 is about 12921.2998959083. The cubic root of 166959991 is about 550.6438641404.

The spelling of 166959991 in words is "one hundred sixty-six million, nine hundred fifty-nine thousand, nine hundred ninety-one".