166763561 has 2 divisors, whose sum is σ = 166763562. Its totient is φ = 166763560.

The previous prime is 166763537. The next prime is 166763563. The reversal of 166763561 is 165367661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85673536 + 81090025 = 9256^2 + 9005^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166763561 is a prime.

It is a Sophie Germain prime.

Together with 166763563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (166763563) 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, 83381780 + 83381781.

It is an arithmetic number, because the mean of its divisors is an integer number (83381781).

Almost surely, 2^166763561 is an apocalyptic number.

It is an amenable number.

166763561 is a deficient number, since it is larger than the sum of its proper divisors (1).

166763561 is an equidigital number, since it uses as much as digits as its factorization.

166763561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 41.

The square root of 166763561 is about 12913.6966434867. The cubic root of 166763561 is about 550.4278335022.

The spelling of 166763561 in words is "one hundred sixty-six million, seven hundred sixty-three thousand, five hundred sixty-one".