166042813 has 2 divisors, whose sum is σ = 166042814. Its totient is φ = 166042812.

The previous prime is 166042787. The next prime is 166042831. The reversal of 166042813 is 318240661.

It is a happy number.

Together with next prime (166042831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138721284 + 27321529 = 11778^2 + 5227^2 .

It is a cyclic number.

It is not a de Polignac number, because 166042813 - 2⁵ = 166042781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166042853) 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, 83021406 + 83021407.

It is an arithmetic number, because the mean of its divisors is an integer number (83021407).

Almost surely, 2^166042813 is an apocalyptic number.

It is an amenable number.

166042813 is a deficient number, since it is larger than the sum of its proper divisors (1).

166042813 is an equidigital number, since it uses as much as digits as its factorization.

166042813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 166042813 is about 12885.7600862347. The cubic root of 166042813 is about 549.6337098305.

The spelling of 166042813 in words is "one hundred sixty-six million, forty-two thousand, eight hundred thirteen".