166733981 has 2 divisors, whose sum is σ = 166733982. Its totient is φ = 166733980.

The previous prime is 166733947. The next prime is 166733999. The reversal of 166733981 is 189337661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160528900 + 6205081 = 12670^2 + 2491^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166733981 is a prime.

It is a super-2 number, since 2×166733981² = 55600440840216722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166733081) 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, 83366990 + 83366991.

It is an arithmetic number, because the mean of its divisors is an integer number (83366991).

Almost surely, 2^166733981 is an apocalyptic number.

It is an amenable number.

166733981 is a deficient number, since it is larger than the sum of its proper divisors (1).

166733981 is an equidigital number, since it uses as much as digits as its factorization.

166733981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 44.

The square root of 166733981 is about 12912.5512970907. The cubic root of 166733981 is about 550.3952871873.

The spelling of 166733981 in words is "one hundred sixty-six million, seven hundred thirty-three thousand, nine hundred eighty-one".