128909685 has 8 divisors (see below), whose sum is σ = 206255520. Its totient is φ = 68751824.

The previous prime is 128909681. The next prime is 128909689. The reversal of 128909685 is 586909821.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (128909681) and next prime (128909689).

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

It is a cyclic number.

It is not a de Polignac number, because 128909685 - 2² = 128909681 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128909681) 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, 4296975 + ... + 4297004.

It is an arithmetic number, because the mean of its divisors is an integer number (25781940).

Almost surely, 2^128909685 is an apocalyptic number.

128909685 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128909685 is a deficient number, since it is larger than the sum of its proper divisors (77345835).

128909685 is an equidigital number, since it uses as much as digits as its factorization.

128909685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8593987.

The product of its (nonzero) digits is 311040, while the sum is 48.

The square root of 128909685 is about 11353.8400992792. The cubic root of 128909685 is about 505.1594895390.

The spelling of 128909685 in words is "one hundred twenty-eight million, nine hundred nine thousand, six hundred eighty-five".