166278689 has 2 divisors, whose sum is σ = 166278690. Its totient is φ = 166278688.

The previous prime is 166278677. The next prime is 166278691. The reversal of 166278689 is 986872661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158961664 + 7317025 = 12608^2 + 2705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166278689 is a prime.

Together with 166278691, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166278689.

It is not a weakly prime, because it can be changed into another prime (166275689) 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, 83139344 + 83139345.

It is an arithmetic number, because the mean of its divisors is an integer number (83139345).

Almost surely, 2^166278689 is an apocalyptic number.

It is an amenable number.

166278689 is a deficient number, since it is larger than the sum of its proper divisors (1).

166278689 is an equidigital number, since it uses as much as digits as its factorization.

166278689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 53.

The square root of 166278689 is about 12894.9094219386. The cubic root of 166278689 is about 549.8938516913.

The spelling of 166278689 in words is "one hundred sixty-six million, two hundred seventy-eight thousand, six hundred eighty-nine".