165215320155665 has 8 divisors (see below), whose sum is σ = 213509029124328. Its totient is φ = 122005159499520.

The previous prime is 165215320155661. The next prime is 165215320155673. The reversal of 165215320155665 is 566551023512561.

It can be written as a sum of positive squares in 4 ways, for example, as 55830784 + 165215264324881 = 7472^2 + 12853609^2 .

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

It is not a de Polignac number, because 165215320155665 - 2² = 165215320155661 is a prime.

It is a super-2 number, since 2×165215320155665² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165215320155661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1270887078056 + ... + 1270887078185.

It is an arithmetic number, because the mean of its divisors is an integer number (26688628640541).

Almost surely, 2^{165215320155665} is an apocalyptic number.

It is an amenable number.

165215320155665 is a deficient number, since it is larger than the sum of its proper divisors (48293708968663).

165215320155665 is a wasteful number, since it uses less digits than its factorization.

165215320155665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2541774156259.

The product of its (nonzero) digits is 8100000, while the sum is 53.

The spelling of 165215320155665 in words is "one hundred sixty-five trillion, two hundred fifteen billion, three hundred twenty million, one hundred fifty-five thousand, six hundred sixty-five".