128728247 has 4 divisors (see below), whose sum is σ = 128792016. Its totient is φ = 128664480.

The previous prime is 128728241. The next prime is 128728277. The reversal of 128728247 is 742827821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 742827821 = 211 ⋅3520511.

It is a cyclic number.

It is not a de Polignac number, because 128728247 - 2⁴ = 128728231 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128728241) 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 3 ways as a sum of consecutive naturals, for example, 28754 + ... + 32927.

It is an arithmetic number, because the mean of its divisors is an integer number (32198004).

Almost surely, 2^128728247 is an apocalyptic number.

128728247 is a deficient number, since it is larger than the sum of its proper divisors (63769).

128728247 is an equidigital number, since it uses as much as digits as its factorization.

128728247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63768.

The product of its digits is 100352, while the sum is 41.

The square root of 128728247 is about 11345.8471257108. The cubic root of 128728247 is about 504.9223773776.

The spelling of 128728247 in words is "one hundred twenty-eight million, seven hundred twenty-eight thousand, two hundred forty-seven".