165561005611 has 4 divisors (see below), whose sum is σ = 175299888312. Its totient is φ = 155822122912.

The previous prime is 165561005591. The next prime is 165561005653. The reversal of 165561005611 is 116500165561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165561005611 - 2¹¹ = 165561003563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165561009611) 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, 4869441325 + ... + 4869441358.

It is an arithmetic number, because the mean of its divisors is an integer number (43824972078).

Almost surely, 2^165561005611 is an apocalyptic number.

165561005611 is a deficient number, since it is larger than the sum of its proper divisors (9738882701).

165561005611 is an equidigital number, since it uses as much as digits as its factorization.

165561005611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9738882700.

The product of its (nonzero) digits is 27000, while the sum is 37.

The spelling of 165561005611 in words is "one hundred sixty-five billion, five hundred sixty-one million, five thousand, six hundred eleven".