128856658821 has 16 divisors (see below), whose sum is σ = 195576906240. Its totient is φ = 74699511920.

The previous prime is 128856658807. The next prime is 128856658829.

128856658821 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 128856658821 - 2²⁶ = 128789549957 is a prime.

It is a super-2 number, since 2×128856658821² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128856658829) 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, 84885051 + ... + 84886568.

It is an arithmetic number, because the mean of its divisors is an integer number (12223556640).

Almost surely, 2^128856658821 is an apocalyptic number.

128856658821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128856658821 is a deficient number, since it is larger than the sum of its proper divisors (66720247419).

128856658821 is a wasteful number, since it uses less digits than its factorization.

128856658821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169771656.

The product of its digits is 14745600, while the sum is 60.

The spelling of 128856658821 in words is "one hundred twenty-eight billion, eight hundred fifty-six million, six hundred fifty-eight thousand, eight hundred twenty-one".