128039831 has 4 divisors (see below), whose sum is σ = 128070552. Its totient is φ = 128009112.

The previous prime is 128039819. The next prime is 128039833. The reversal of 128039831 is 138930821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128039831 is a prime.

It is a super-2 number, since 2×128039831² = 32788396645017122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 128039791 and 128039800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128039833) 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, 7901 + ... + 17846.

It is an arithmetic number, because the mean of its divisors is an integer number (32017638).

Almost surely, 2^128039831 is an apocalyptic number.

128039831 is a deficient number, since it is larger than the sum of its proper divisors (30721).

128039831 is an equidigital number, since it uses as much as digits as its factorization.

128039831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30720.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 128039831 is about 11315.4686602014. The cubic root of 128039831 is about 504.0206894484.

The spelling of 128039831 in words is "one hundred twenty-eight million, thirty-nine thousand, eight hundred thirty-one".