166598561 has 2 divisors, whose sum is σ = 166598562. Its totient is φ = 166598560.

The previous prime is 166598527. The next prime is 166598563. The reversal of 166598561 is 165895661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 166539025 + 59536 = 12905^2 + 244^2 .

It is a cyclic number.

It is not a de Polignac number, because 166598561 - 2¹⁰ = 166597537 is a prime.

Together with 166598563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166598563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83299280 + 83299281.

It is an arithmetic number, because the mean of its divisors is an integer number (83299281).

Almost surely, 2^166598561 is an apocalyptic number.

It is an amenable number.

166598561 is a deficient number, since it is larger than the sum of its proper divisors (1).

166598561 is an equidigital number, since it uses as much as digits as its factorization.

166598561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 47.

The square root of 166598561 is about 12907.3064967095. The cubic root of 166598561 is about 550.2462379509.

The spelling of 166598561 in words is "one hundred sixty-six million, five hundred ninety-eight thousand, five hundred sixty-one".