128257139 has 4 divisors (see below), whose sum is σ = 129433920. Its totient is φ = 127080360.

The previous prime is 128257123. The next prime is 128257141. The reversal of 128257139 is 931752821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931752821 = 1531 ⋅608591.

It is a cyclic number.

It is not a de Polignac number, because 128257139 - 2⁴ = 128257123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128257159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 588227 + ... + 588444.

It is an arithmetic number, because the mean of its divisors is an integer number (32358480).

Almost surely, 2^128257139 is an apocalyptic number.

128257139 is a deficient number, since it is larger than the sum of its proper divisors (1176781).

128257139 is a wasteful number, since it uses less digits than its factorization.

128257139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1176780.

The product of its digits is 30240, while the sum is 38.

The square root of 128257139 is about 11325.0668430698. The cubic root of 128257139 is about 504.3056680168.

The spelling of 128257139 in words is "one hundred twenty-eight million, two hundred fifty-seven thousand, one hundred thirty-nine".