128131111001 has 4 divisors (see below), whose sum is σ = 128662775604. Its totient is φ = 127599446400.

The previous prime is 128131110973. The next prime is 128131111013. The reversal of 128131111001 is 100111131821.

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 99552870400 + 28578240601 = 315520^2 + 169051^2 .

It is a cyclic number.

It is not a de Polignac number, because 128131111001 - 2⁶ = 128131110937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128131111021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265831940 + ... + 265832421.

It is an arithmetic number, because the mean of its divisors is an integer number (32165693901).

Almost surely, 2^128131111001 is an apocalyptic number.

It is an amenable number.

128131111001 is a deficient number, since it is larger than the sum of its proper divisors (531664603).

128131111001 is an equidigital number, since it uses as much as digits as its factorization.

128131111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531664602.

The product of its (nonzero) digits is 48, while the sum is 20.

Adding to 128131111001 its reverse (100111131821), we get a palindrome (228242242822).

The spelling of 128131111001 in words is "one hundred twenty-eight billion, one hundred thirty-one million, one hundred eleven thousand, one".