128500001 has 12 divisors (see below), whose sum is σ = 153521748. Its totient is φ = 107164512.

The previous prime is 128499971. The next prime is 128500003. The reversal of 128500001 is 100005821.

It can be written as a sum of positive squares in 2 ways, for example, as 123099025 + 5400976 = 11095^2 + 2324^2 .

It is not a de Polignac number, because 128500001 - 2⁶ = 128499937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128500003) 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 11 ways as a sum of consecutive naturals, for example, 33626 + ... + 37251.

It is an arithmetic number, because the mean of its divisors is an integer number (12793479).

Almost surely, 2^128500001 is an apocalyptic number.

It is an amenable number.

128500001 is a deficient number, since it is larger than the sum of its proper divisors (25021747).

128500001 is an equidigital number, since it uses as much as digits as its factorization.

128500001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70928 (or 70921 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 128500001 is about 11335.7840928627. The cubic root of 128500001 is about 504.6237775579.

Adding to 128500001 its reverse (100005821), we get a palindrome (228505822).

The spelling of 128500001 in words is "one hundred twenty-eight million, five hundred thousand, one".