166509707797 has 4 divisors (see below), whose sum is σ = 167429651116. Its totient is φ = 165589764480.

The previous prime is 166509707737. The next prime is 166509707803. The reversal of 166509707797 is 797707905661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 88542548721 + 77967159076 = 297561^2 + 279226^2 .

It is a cyclic number.

It is not a de Polignac number, because 166509707797 - 2²³ = 166501319189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166509707717) 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 in 3 ways as a sum of consecutive naturals, for example, 459971388 + ... + 459971749.

It is an arithmetic number, because the mean of its divisors is an integer number (41857412779).

Almost surely, 2^166509707797 is an apocalyptic number.

It is an amenable number.

166509707797 is a deficient number, since it is larger than the sum of its proper divisors (919943319).

166509707797 is an equidigital number, since it uses as much as digits as its factorization.

166509707797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 919943318.

The product of its (nonzero) digits is 35006580, while the sum is 64.

The spelling of 166509707797 in words is "one hundred sixty-six billion, five hundred nine million, seven hundred seven thousand, seven hundred ninety-seven".