128399999 has 16 divisors (see below), whose sum is σ = 159183360. Its totient is φ = 100850400.

The previous prime is 128399983. The next prime is 128400001. The reversal of 128399999 is 999993821.

It is not a de Polignac number, because 128399999 - 2⁴ = 128399983 is a prime.

128399999 is a modest number, since divided by 99999 gives 1283 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128399959) 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 15 ways as a sum of consecutive naturals, for example, 7574 + ... + 17724.

It is an arithmetic number, because the mean of its divisors is an integer number (9948960).

Almost surely, 2^128399999 is an apocalyptic number.

128399999 is a deficient number, since it is larger than the sum of its proper divisors (30783361).

128399999 is a wasteful number, since it uses less digits than its factorization.

128399999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10310.

The product of its digits is 2834352, while the sum is 59.

The square root of 128399999 is about 11331.3723352470. The cubic root of 128399999 is about 504.4928398591.

The spelling of 128399999 in words is "one hundred twenty-eight million, three hundred ninety-nine thousand, nine hundred ninety-nine".