165221161065685 has 8 divisors (see below), whose sum is σ = 198351259638840. Its totient is φ = 132119684612544.

The previous prime is 165221161065659. The next prime is 165221161065691. The reversal of 165221161065685 is 586560161122561.

It can be written as a sum of positive squares in 4 ways, for example, as 37634715861796 + 127586445203889 = 6134714^2 + 11295417^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165221161065685 - 2³¹ = 165219013582037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7155517302 + ... + 7155540391.

It is an arithmetic number, because the mean of its divisors is an integer number (24793907454855).

Almost surely, 2^{165221161065685} is an apocalyptic number.

It is an amenable number.

165221161065685 is a deficient number, since it is larger than the sum of its proper divisors (33130098573155).

165221161065685 is a wasteful number, since it uses less digits than its factorization.

165221161065685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14311060007.

The product of its (nonzero) digits is 5184000, while the sum is 55.

The spelling of 165221161065685 in words is "one hundred sixty-five trillion, two hundred twenty-one billion, one hundred sixty-one million, sixty-five thousand, six hundred eighty-five".