128421260565 has 128 divisors (see below), whose sum is σ = 228600852480. Its totient is φ = 61173522432.

The previous prime is 128421260533. The next prime is 128421260567. The reversal of 128421260565 is 565062124821.

It is not a de Polignac number, because 128421260565 - 2⁵ = 128421260533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128421260567) 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 127 ways as a sum of consecutive naturals, for example, 363799429 + ... + 363799781.

It is an arithmetic number, because the mean of its divisors is an integer number (1785944160).

Almost surely, 2^128421260565 is an apocalyptic number.

128421260565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128421260565 is a deficient number, since it is larger than the sum of its proper divisors (100179591915).

128421260565 is a wasteful number, since it uses less digits than its factorization.

128421260565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 843.

The product of its (nonzero) digits is 230400, while the sum is 42.

The spelling of 128421260565 in words is "one hundred twenty-eight billion, four hundred twenty-one million, two hundred sixty thousand, five hundred sixty-five".