165055116511661 has 4 divisors (see below), whose sum is σ = 165059437251324. Its totient is φ = 165050795772000.

The previous prime is 165055116511657. The next prime is 165055116511667. The reversal of 165055116511661 is 166115611550561.

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 39056175256036 + 125998941255625 = 6249494^2 + 11224925^2 .

It is a cyclic number.

It is not a de Polignac number, because 165055116511661 - 2² = 165055116511657 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 (165055116511667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2160312530 + ... + 2160388931.

It is an arithmetic number, because the mean of its divisors is an integer number (41264859312831).

Almost surely, 2^{165055116511661} is an apocalyptic number.

It is an amenable number.

165055116511661 is a deficient number, since it is larger than the sum of its proper divisors (4320739663).

165055116511661 is an equidigital number, since it uses as much as digits as its factorization.

165055116511661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4320739662.

The product of its (nonzero) digits is 810000, while the sum is 50.

The spelling of 165055116511661 in words is "one hundred sixty-five trillion, fifty-five billion, one hundred sixteen million, five hundred eleven thousand, six hundred sixty-one".