16505644161 has 4 divisors (see below), whose sum is σ = 22007525552. Its totient is φ = 11003762772.

The previous prime is 16505644153. The next prime is 16505644163. The reversal of 16505644161 is 16144650561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 16505644161 - 2³ = 16505644153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16505644163) 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, 2750940691 + ... + 2750940696.

It is an arithmetic number, because the mean of its divisors is an integer number (5501881388).

Almost surely, 2^16505644161 is an apocalyptic number.

It is an amenable number.

16505644161 is a deficient number, since it is larger than the sum of its proper divisors (5501881391).

16505644161 is an equidigital number, since it uses as much as digits as its factorization.

16505644161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5501881390.

The product of its (nonzero) digits is 86400, while the sum is 39.

The spelling of 16505644161 in words is "sixteen billion, five hundred five million, six hundred forty-four thousand, one hundred sixty-one".