166204993 has 2 divisors, whose sum is σ = 166204994. Its totient is φ = 166204992.

The previous prime is 166204991. The next prime is 166205009. The reversal of 166204993 is 399402661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121154049 + 45050944 = 11007^2 + 6712^2 .

It is a cyclic number.

It is not a de Polignac number, because 166204993 - 2¹ = 166204991 is a prime.

Together with 166204991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (166204991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83102496 + 83102497.

It is an arithmetic number, because the mean of its divisors is an integer number (83102497).

Almost surely, 2^166204993 is an apocalyptic number.

It is an amenable number.

166204993 is a deficient number, since it is larger than the sum of its proper divisors (1).

166204993 is an equidigital number, since it uses as much as digits as its factorization.

166204993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 166204993 is about 12892.0515434899. The cubic root of 166204993 is about 549.8126006182.

The spelling of 166204993 in words is "one hundred sixty-six million, two hundred four thousand, nine hundred ninety-three".