166613891 has 2 divisors, whose sum is σ = 166613892. Its totient is φ = 166613890.

The previous prime is 166613851. The next prime is 166613899. The reversal of 166613891 is 198316661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 166613891 - 2⁶ = 166613827 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166613899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83306945 + 83306946.

It is an arithmetic number, because the mean of its divisors is an integer number (83306946).

Almost surely, 2^166613891 is an apocalyptic number.

166613891 is a deficient number, since it is larger than the sum of its proper divisors (1).

166613891 is an equidigital number, since it uses as much as digits as its factorization.

166613891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 41.

The square root of 166613891 is about 12907.9003327420. The cubic root of 166613891 is about 550.2631148796.

The spelling of 166613891 in words is "one hundred sixty-six million, six hundred thirteen thousand, eight hundred ninety-one".