166723121 has 2 divisors, whose sum is σ = 166723122. Its totient is φ = 166723120.

The previous prime is 166723111. The next prime is 166723171. The reversal of 166723121 is 121327661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160149025 + 6574096 = 12655^2 + 2564^2 .

It is a cyclic number.

It is not a de Polignac number, because 166723121 - 2¹⁰ = 166722097 is a prime.

It is not a weakly prime, because it can be changed into another prime (166723111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83361560 + 83361561.

It is an arithmetic number, because the mean of its divisors is an integer number (83361561).

Almost surely, 2^166723121 is an apocalyptic number.

It is an amenable number.

166723121 is a deficient number, since it is larger than the sum of its proper divisors (1).

166723121 is an equidigital number, since it uses as much as digits as its factorization.

166723121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 29.

The square root of 166723121 is about 12912.1307691643. The cubic root of 166723121 is about 550.3833371686.

The spelling of 166723121 in words is "one hundred sixty-six million, seven hundred twenty-three thousand, one hundred twenty-one".