161611100500109 has 4 divisors (see below), whose sum is σ = 174042723615516. Its totient is φ = 149179477384704.

The previous prime is 161611100500067. The next prime is 161611100500153. The reversal of 161611100500109 is 901005001116161.

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 38026301903209 + 123584798596900 = 6166547^2 + 11116870^2 .

It is not a de Polignac number, because 161611100500109 - 2¹⁶ = 161611100434573 is a prime.

It is a super-2 number, since 2×161611100500109² (a number of 29 digits) contains 22 as substring.

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 (161611100500189) 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, 6215811557684 + ... + 6215811557709.

It is an arithmetic number, because the mean of its divisors is an integer number (43510680903879).

Almost surely, 2^{161611100500109} is an apocalyptic number.

It is an amenable number.

161611100500109 is a deficient number, since it is larger than the sum of its proper divisors (12431623115407).

161611100500109 is a wasteful number, since it uses less digits than its factorization.

161611100500109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12431623115406.

The product of its (nonzero) digits is 1620, while the sum is 32.

The spelling of 161611100500109 in words is "one hundred sixty-one trillion, six hundred eleven billion, one hundred million, five hundred thousand, one hundred nine".