165424121 has 4 divisors (see below), whose sum is σ = 166534500. Its totient is φ = 164313744.

The previous prime is 165424117. The next prime is 165424159. The reversal of 165424121 is 121424561.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21160000 + 144264121 = 4600^2 + 12011^2 .

It is a cyclic number.

It is not a de Polignac number, because 165424121 - 2² = 165424117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165424421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 554966 + ... + 555263.

It is an arithmetic number, because the mean of its divisors is an integer number (41633625).

Almost surely, 2^165424121 is an apocalyptic number.

It is an amenable number.

165424121 is a deficient number, since it is larger than the sum of its proper divisors (1110379).

165424121 is a wasteful number, since it uses less digits than its factorization.

165424121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110378.

The product of its digits is 1920, while the sum is 26.

The square root of 165424121 is about 12861.7308710764. The cubic root of 165424121 is about 548.9501969303.

Adding to 165424121 its reverse (121424561), we get a palindrome (286848682).

The spelling of 165424121 in words is "one hundred sixty-five million, four hundred twenty-four thousand, one hundred twenty-one".