165641011 has 4 divisors (see below), whose sum is σ = 171352800. Its totient is φ = 159929224.

The previous prime is 165640961. The next prime is 165641023. The reversal of 165641011 is 110146561.

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 165641011 - 2¹⁵ = 165608243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165641071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2855851 + ... + 2855908.

It is an arithmetic number, because the mean of its divisors is an integer number (42838200).

Almost surely, 2^165641011 is an apocalyptic number.

165641011 is a deficient number, since it is larger than the sum of its proper divisors (5711789).

165641011 is an equidigital number, since it uses as much as digits as its factorization.

165641011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5711788.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 165641011 is about 12870.1597115187. The cubic root of 165641011 is about 549.1900043836.

Adding to 165641011 its reverse (110146561), we get a palindrome (275787572).

The spelling of 165641011 in words is "one hundred sixty-five million, six hundred forty-one thousand, eleven".