161611105611505 has 16 divisors (see below), whose sum is σ = 212202794230848. Its totient is φ = 117180257832000.

The previous prime is 161611105611493. The next prime is 161611105611511. The reversal of 161611105611505 is 505116501116161.

It is a happy number.

It is not a de Polignac number, because 161611105611505 - 2⁹ = 161611105610993 is a prime.

It is a super-3 number, since 3×161611105611505³ (a number of 44 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4438627926 + ... + 4438664335.

It is an arithmetic number, because the mean of its divisors is an integer number (13262674639428).

Almost surely, 2^{161611105611505} is an apocalyptic number.

It is an amenable number.

161611105611505 is a deficient number, since it is larger than the sum of its proper divisors (50591688619343).

161611105611505 is a wasteful number, since it uses less digits than its factorization.

161611105611505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8877292608.

The product of its (nonzero) digits is 27000, while the sum is 40.

Adding to 161611105611505 its reverse (505116501116161), we get a palindrome (666727606727666).

The spelling of 161611105611505 in words is "one hundred sixty-one trillion, six hundred eleven billion, one hundred five million, six hundred eleven thousand, five hundred five".