166845991 has 8 divisors (see below), whose sum is σ = 180614000. Its totient is φ = 153211392.

The previous prime is 166845983. The next prime is 166846003. The reversal of 166845991 is 199548661.

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 166845991 - 2³ = 166845983 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 (166845391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30741 + ... + 35758.

It is an arithmetic number, because the mean of its divisors is an integer number (22576750).

Almost surely, 2^166845991 is an apocalyptic number.

166845991 is a deficient number, since it is larger than the sum of its proper divisors (13768009).

166845991 is a wasteful number, since it uses less digits than its factorization.

166845991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66705.

The product of its digits is 466560, while the sum is 49.

The square root of 166845991 is about 12916.8878217626. The cubic root of 166845991 is about 550.5185093717.

The spelling of 166845991 in words is "one hundred sixty-six million, eight hundred forty-five thousand, nine hundred ninety-one".