128178871821 has 256 divisors, whose sum is σ = 273288314880. Its totient is φ = 57192791040.

The previous prime is 128178871801. The next prime is 128178871879.

128178871821 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 128178871821 - 2⁹ = 128178871309 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128178871801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 22997191 + ... + 23002763.

It is an arithmetic number, because the mean of its divisors is an integer number (1067532480).

Almost surely, 2^128178871821 is an apocalyptic number.

128178871821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128178871821 is an abundant number, since it is smaller than the sum of its proper divisors (145109443059).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128178871821 is a wasteful number, since it uses less digits than its factorization.

128178871821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5673 (or 5667 counting only the distinct ones).

The product of its digits is 802816, while the sum is 54.

It can be divided in two parts, 128178 and 871821, that added together give a palindrome (999999).

The spelling of 128178871821 in words is "one hundred twenty-eight billion, one hundred seventy-eight million, eight hundred seventy-one thousand, eight hundred twenty-one".