166561859 has 2 divisors, whose sum is σ = 166561860. Its totient is φ = 166561858.

The previous prime is 166561831. The next prime is 166561867. The reversal of 166561859 is 958165661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166561859 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166561259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83280929 + 83280930.

It is an arithmetic number, because the mean of its divisors is an integer number (83280930).

Almost surely, 2^166561859 is an apocalyptic number.

166561859 is a deficient number, since it is larger than the sum of its proper divisors (1).

166561859 is an equidigital number, since it uses as much as digits as its factorization.

166561859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 47.

The square root of 166561859 is about 12905.8846655315. The cubic root of 166561859 is about 550.2058281968.

The spelling of 166561859 in words is "one hundred sixty-six million, five hundred sixty-one thousand, eight hundred fifty-nine".