165401 has 4 divisors (see below), whose sum is σ = 166452. Its totient is φ = 164352.

The previous prime is 165397. The next prime is 165437. The reversal of 165401 is 104561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 102400 + 63001 = 320^2 + 251^2 .

It is a cyclic number.

It is not a de Polignac number, because 165401 - 2² = 165397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165401.

It is not an unprimeable number, because it can be changed into a prime (165001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236 + ... + 621.

It is an arithmetic number, because the mean of its divisors is an integer number (41613).

2¹⁶⁵⁴⁰¹ is an apocalyptic number.

It is an amenable number.

165401 is a deficient number, since it is larger than the sum of its proper divisors (1051).

165401 is an equidigital number, since it uses as much as digits as its factorization.

165401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 165401 is about 406.6952175770. The cubic root of 165401 is about 54.8924620513.

Adding to 165401 its reverse (104561), we get a palindrome (269962).

The spelling of 165401 in words is "one hundred sixty-five thousand, four hundred one".