165601611 has 16 divisors (see below), whose sum is σ = 280384000. Its totient is φ = 94629384.

The previous prime is 165601609. The next prime is 165601621. The reversal of 165601611 is 116106561.

165601611 is a `hidden beast` number, since 1 + 656 + 0 + 1 + 6 + 1 + 1 = 666.

It is not a de Polignac number, because 165601611 - 2¹ = 165601609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165601621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 437911 + ... + 438288.

It is an arithmetic number, because the mean of its divisors is an integer number (17524000).

Almost surely, 2^165601611 is an apocalyptic number.

165601611 is a deficient number, since it is larger than the sum of its proper divisors (114782389).

165601611 is an equidigital number, since it uses as much as digits as its factorization.

165601611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 876215 (or 876209 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 165601611 is about 12868.6289479494. The cubic root of 165601611 is about 549.1464567905.

The spelling of 165601611 in words is "one hundred sixty-five million, six hundred one thousand, six hundred eleven".