166556387 has 2 divisors, whose sum is σ = 166556388. Its totient is φ = 166556386.

The previous prime is 166556371. The next prime is 166556389. The reversal of 166556387 is 783655661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 166556387 - 2⁴ = 166556371 is a prime.

Together with 166556389, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166556389) 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 as a sum of consecutive naturals, namely, 83278193 + 83278194.

It is an arithmetic number, because the mean of its divisors is an integer number (83278194).

Almost surely, 2^166556387 is an apocalyptic number.

166556387 is a deficient number, since it is larger than the sum of its proper divisors (1).

166556387 is an equidigital number, since it uses as much as digits as its factorization.

166556387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 47.

The square root of 166556387 is about 12905.6726674746. The cubic root of 166556387 is about 550.1998028893.

The spelling of 166556387 in words is "one hundred sixty-six million, five hundred fifty-six thousand, three hundred eighty-seven".