128726557 has 2 divisors, whose sum is σ = 128726558. Its totient is φ = 128726556.

The previous prime is 128726519. The next prime is 128726569. The reversal of 128726557 is 755627821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87497316 + 41229241 = 9354^2 + 6421^2 .

It is a cyclic number.

It is not a de Polignac number, because 128726557 - 2¹¹ = 128724509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128723557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64363278 + 64363279.

It is an arithmetic number, because the mean of its divisors is an integer number (64363279).

Almost surely, 2^128726557 is an apocalyptic number.

It is an amenable number.

128726557 is a deficient number, since it is larger than the sum of its proper divisors (1).

128726557 is an equidigital number, since it uses as much as digits as its factorization.

128726557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 235200, while the sum is 43.

The square root of 128726557 is about 11345.7726488768. The cubic root of 128726557 is about 504.9201677550.

The spelling of 128726557 in words is "one hundred twenty-eight million, seven hundred twenty-six thousand, five hundred fifty-seven".