161111605 has 4 divisors (see below), whose sum is σ = 193333932. Its totient is φ = 128889280.

The previous prime is 161111597. The next prime is 161111611. The reversal of 161111605 is 506111161.

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 96373489 + 64738116 = 9817^2 + 8046^2 .

It is not a de Polignac number, because 161111605 - 2³ = 161111597 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16111156 + ... + 16111165.

It is an arithmetic number, because the mean of its divisors is an integer number (48333483).

Almost surely, 2^161111605 is an apocalyptic number.

It is an amenable number.

161111605 is a deficient number, since it is larger than the sum of its proper divisors (32222327).

161111605 is an equidigital number, since it uses as much as digits as its factorization.

161111605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32222326.

The product of its (nonzero) digits is 180, while the sum is 22.

The square root of 161111605 is about 12692.9746316614. The cubic root of 161111605 is about 544.1378563634.

Adding to 161111605 its reverse (506111161), we get a palindrome (667222766).

The spelling of 161111605 in words is "one hundred sixty-one million, one hundred eleven thousand, six hundred five".