128001 has 4 divisors (see below), whose sum is σ = 170672. Its totient is φ = 85332.

The previous prime is 127997. The next prime is 128021. The reversal of 128001 is 100821.

It is a happy number.

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 128001 - 2² = 127997 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128021) 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, 21331 + ... + 21336.

It is an arithmetic number, because the mean of its divisors is an integer number (42668).

It is a Proth number, since it is equal to 125 ⋅ 2¹⁰ + 1 and 125 < 2¹⁰.

2¹²⁸⁰⁰¹ is an apocalyptic number.

It is an amenable number.

128001 is a deficient number, since it is larger than the sum of its proper divisors (42671).

128001 is an equidigital number, since it uses as much as digits as its factorization.

128001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42670.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 128001 is about 357.7722739397. The cubic root of 128001 is about 50.3969732372.

Adding to 128001 its reverse (100821), we get a palindrome (228822).

The spelling of 128001 in words is "one hundred twenty-eight thousand, one".