128639287 has 8 divisors (see below), whose sum is σ = 147098016. Its totient is φ = 110200992.

The previous prime is 128639279. The next prime is 128639309. The reversal of 128639287 is 782936821.

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 128639287 - 2³ = 128639279 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 (128639387) 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, 12393 + ... + 20269.

It is an arithmetic number, because the mean of its divisors is an integer number (18387252).

Almost surely, 2^128639287 is an apocalyptic number.

128639287 is a deficient number, since it is larger than the sum of its proper divisors (18458729).

128639287 is an equidigital number, since it uses as much as digits as its factorization.

128639287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10217.

The product of its digits is 290304, while the sum is 46.

The square root of 128639287 is about 11341.9260709987. The cubic root of 128639287 is about 504.8060386387.

The spelling of 128639287 in words is "one hundred twenty-eight million, six hundred thirty-nine thousand, two hundred eighty-seven".