161015611605505 has 4 divisors (see below), whose sum is σ = 193218733926612. Its totient is φ = 128812489284400.

The previous prime is 161015611605481. The next prime is 161015611605521. The reversal of 161015611605505 is 505506116510161.

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 70178166772081 + 90837444833424 = 8377241^2 + 9530868^2 .

It is not a de Polignac number, because 161015611605505 - 2¹⁹ = 161015611081217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16101561160546 + ... + 16101561160555.

It is an arithmetic number, because the mean of its divisors is an integer number (48304683481653).

Almost surely, 2^{161015611605505} is an apocalyptic number.

It is an amenable number.

161015611605505 is a deficient number, since it is larger than the sum of its proper divisors (32203122321107).

161015611605505 is an equidigital number, since it uses as much as digits as its factorization.

161015611605505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32203122321106.

The product of its (nonzero) digits is 135000, while the sum is 43.

The spelling of 161015611605505 in words is "one hundred sixty-one trillion, fifteen billion, six hundred eleven million, six hundred five thousand, five hundred five".