161165555661509 has 8 divisors (see below), whose sum is σ = 184542736621248. Its totient is φ = 137876757239520.

The previous prime is 161165555661437. The next prime is 161165555661511. The reversal of 161165555661509 is 905166555561161.

161165555661509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 161165555661509 - 2¹⁶ = 161165555595973 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161165555661599) 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, 22095630527 + ... + 22095637820.

It is an arithmetic number, because the mean of its divisors is an integer number (23067842077656).

Almost surely, 2^{161165555661509} is an apocalyptic number.

It is an amenable number.

161165555661509 is a deficient number, since it is larger than the sum of its proper divisors (23377180959739).

161165555661509 is an equidigital number, since it uses as much as digits as its factorization.

161165555661509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44191268875.

The product of its (nonzero) digits is 36450000, while the sum is 62.

The spelling of 161165555661509 in words is "one hundred sixty-one trillion, one hundred sixty-five billion, five hundred fifty-five million, six hundred sixty-one thousand, five hundred nine".