128361 has 4 divisors (see below), whose sum is σ = 171152. Its totient is φ = 85572.

The previous prime is 128351. The next prime is 128377. The reversal of 128361 is 163821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 128361 - 2⁹ = 127849 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21391 + ... + 21396.

It is an arithmetic number, because the mean of its divisors is an integer number (42788).

2¹²⁸³⁶¹ is an apocalyptic number.

It is an amenable number.

128361 is a deficient number, since it is larger than the sum of its proper divisors (42791).

128361 is an equidigital number, since it uses as much as digits as its factorization.

128361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42790.

The product of its digits is 288, while the sum is 21.

The square root of 128361 is about 358.2750340172. The cubic root of 128361 is about 50.4441758061. Note that the first 3 decimals are identical.

The spelling of 128361 in words is "one hundred twenty-eight thousand, three hundred sixty-one".