166673561 has 2 divisors, whose sum is σ = 166673562. Its totient is φ = 166673560.

The previous prime is 166673543. The next prime is 166673587. The reversal of 166673561 is 165376661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 96432400 + 70241161 = 9820^2 + 8381^2 .

It is a cyclic number.

It is not a de Polignac number, because 166673561 - 2⁶ = 166673497 is a prime.

It is not a weakly prime, because it can be changed into another prime (166673861) 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, 83336780 + 83336781.

It is an arithmetic number, because the mean of its divisors is an integer number (83336781).

Almost surely, 2^166673561 is an apocalyptic number.

It is an amenable number.

166673561 is a deficient number, since it is larger than the sum of its proper divisors (1).

166673561 is an equidigital number, since it uses as much as digits as its factorization.

166673561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 41.

The square root of 166673561 is about 12910.2115009786. The cubic root of 166673561 is about 550.3287962402.

The spelling of 166673561 in words is "one hundred sixty-six million, six hundred seventy-three thousand, five hundred sixty-one".