128405405569 has 45 divisors (see below), whose sum is σ = 153426368769. Its totient is φ = 107458099560.

The previous prime is 128405405563. The next prime is 128405405573. The reversal of 128405405569 is 965504504821.

It is a happy number.

The square root of 128405405569 is 358337.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 128405405569 - 2³ = 128405405561 is a prime.

It is a super-2 number, since 2×128405405569² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128405405561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1246654372 + ... + 1246654474.

Almost surely, 2^128405405569 is an apocalyptic number.

128405405569 is the 358337-th square number.

128405405569 is the 179169-th centered octagonal number.

It is an amenable number.

128405405569 is a deficient number, since it is larger than the sum of its proper divisors (25020963200).

128405405569 is an frugal number, since it uses more digits than its factorization.

128405405569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 1728000, while the sum is 49.

Multiplying 128405405569 by its sum of digits (49), we get a square (6291864872881 = 2508359²).

128405405569 divided by its sum of digits (49) gives a square (2620518481 = 51191²).

The spelling of 128405405569 in words is "one hundred twenty-eight billion, four hundred five million, four hundred five thousand, five hundred sixty-nine".