128668133561 has 16 divisors (see below), whose sum is σ = 143896946688. Its totient is φ = 114046870800.

The previous prime is 128668133509. The next prime is 128668133567. The reversal of 128668133561 is 165331866821.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128668133561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128668133567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337175 + ... + 609116.

It is an arithmetic number, because the mean of its divisors is an integer number (8993559168).

Almost surely, 2^128668133561 is an apocalyptic number.

128668133561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128668133561 is a deficient number, since it is larger than the sum of its proper divisors (15228813127).

128668133561 is a wasteful number, since it uses less digits than its factorization.

128668133561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946612.

The product of its digits is 1244160, while the sum is 50.

The spelling of 128668133561 in words is "one hundred twenty-eight billion, six hundred sixty-eight million, one hundred thirty-three thousand, five hundred sixty-one".