166339891 has 4 divisors (see below), whose sum is σ = 166747000. Its totient is φ = 165932784.

The previous prime is 166339879. The next prime is 166339897. The reversal of 166339891 is 198933661.

166339891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198933661 = 181 ⋅1099081.

It is a cyclic number.

It is not a de Polignac number, because 166339891 - 2⁷ = 166339763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166339897) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202941 + ... + 203758.

It is an arithmetic number, because the mean of its divisors is an integer number (41686750).

Almost surely, 2^166339891 is an apocalyptic number.

166339891 is a deficient number, since it is larger than the sum of its proper divisors (407109).

166339891 is an equidigital number, since it uses as much as digits as its factorization.

166339891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407108.

The product of its digits is 209952, while the sum is 46.

The square root of 166339891 is about 12897.2823106265. The cubic root of 166339891 is about 549.9613096750.

The spelling of 166339891 in words is "one hundred sixty-six million, three hundred thirty-nine thousand, eight hundred ninety-one".