128566939 has 8 divisors (see below), whose sum is σ = 138635280. Its totient is φ = 118828800.

The previous prime is 128566927. The next prime is 128566961. The reversal of 128566939 is 939665821.

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 128566939 - 2²¹ = 126469787 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 128566892 and 128566901.

It is not an unprimeable number, because it can be changed into a prime (128566909) 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, 81742 + ... + 83299.

It is an arithmetic number, because the mean of its divisors is an integer number (17329410).

Almost surely, 2^128566939 is an apocalyptic number.

128566939 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

128566939 is a deficient number, since it is larger than the sum of its proper divisors (10068341).

128566939 is a wasteful number, since it uses less digits than its factorization.

128566939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165101.

The product of its digits is 699840, while the sum is 49.

The square root of 128566939 is about 11338.7362170570. The cubic root of 128566939 is about 504.7113849316.

The spelling of 128566939 in words is "one hundred twenty-eight million, five hundred sixty-six thousand, nine hundred thirty-nine".