128873378821 has 4 divisors (see below), whose sum is σ = 140589140544. Its totient is φ = 117157617100.

The previous prime is 128873378749. The next prime is 128873378849.

128873378821 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128873378821 - 2¹³ = 128873370629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128873372821) 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, 5857880845 + ... + 5857880866.

It is an arithmetic number, because the mean of its divisors is an integer number (35147285136).

Almost surely, 2^128873378821 is an apocalyptic number.

128873378821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128873378821 is a deficient number, since it is larger than the sum of its proper divisors (11715761723).

128873378821 is a wasteful number, since it uses less digits than its factorization.

128873378821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11715761722.

The product of its digits is 7225344, while the sum is 58.

The spelling of 128873378821 in words is "one hundred twenty-eight billion, eight hundred seventy-three million, three hundred seventy-eight thousand, eight hundred twenty-one".