128405823 has 64 divisors (see below), whose sum is σ = 223104000. Its totient is φ = 65197440.

The previous prime is 128405801. The next prime is 128405861. The reversal of 128405823 is 328504821.

It is not a de Polignac number, because 128405823 - 2⁵ = 128405791 is a prime.

It is a super-3 number, since 3×128405823³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128405863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 387768 + ... + 388098.

It is an arithmetic number, because the mean of its divisors is an integer number (3486000).

Almost surely, 2^128405823 is an apocalyptic number.

128405823 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

128405823 is a deficient number, since it is larger than the sum of its proper divisors (94698177).

128405823 is a wasteful number, since it uses less digits than its factorization.

128405823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 128405823 is about 11331.6293179754. The cubic root of 128405823 is about 504.5004673822.

The spelling of 128405823 in words is "one hundred twenty-eight million, four hundred five thousand, eight hundred twenty-three".