128720539 has 2 divisors, whose sum is σ = 128720540. Its totient is φ = 128720538.

The previous prime is 128720519. The next prime is 128720551. The reversal of 128720539 is 935027821.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128720539 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 128720498 and 128720507.

It is not a weakly prime, because it can be changed into another prime (128720509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64360269 + 64360270.

It is an arithmetic number, because the mean of its divisors is an integer number (64360270).

Almost surely, 2^128720539 is an apocalyptic number.

128720539 is a deficient number, since it is larger than the sum of its proper divisors (1).

128720539 is an equidigital number, since it uses as much as digits as its factorization.

128720539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 128720539 is about 11345.5074368668. The cubic root of 128720539 is about 504.9122992493.

The spelling of 128720539 in words is "one hundred twenty-eight million, seven hundred twenty thousand, five hundred thirty-nine".