128563365821 has 8 divisors (see below), whose sum is σ = 142550141088. Its totient is φ = 114959790000.

The previous prime is 128563365743. The next prime is 128563365863.

128563365821 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-128563365821 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 128563365821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128563368821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95799155 + ... + 95800496.

It is an arithmetic number, because the mean of its divisors is an integer number (17818767636).

Almost surely, 2^128563365821 is an apocalyptic number.

128563365821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128563365821 is a deficient number, since it is larger than the sum of its proper divisors (13986775267).

128563365821 is a wasteful number, since it uses less digits than its factorization.

128563365821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191599723.

The product of its digits is 2073600, while the sum is 50.

The spelling of 128563365821 in words is "one hundred twenty-eight billion, five hundred sixty-three million, three hundred sixty-five thousand, eight hundred twenty-one".