128731081 has 2 divisors, whose sum is σ = 128731082. Its totient is φ = 128731080.

The previous prime is 128731067. The next prime is 128731171. The reversal of 128731081 is 180137821.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114169225 + 14561856 = 10685^2 + 3816^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128731081 is a prime.

It is a super-2 number, since 2×128731081² = 33143382430857122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (128731181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64365540 + 64365541.

It is an arithmetic number, because the mean of its divisors is an integer number (64365541).

Almost surely, 2^128731081 is an apocalyptic number.

It is an amenable number.

128731081 is a deficient number, since it is larger than the sum of its proper divisors (1).

128731081 is an equidigital number, since it uses as much as digits as its factorization.

128731081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 31.

The square root of 128731081 is about 11345.9720165352. The cubic root of 128731081 is about 504.9260827014.

The spelling of 128731081 in words is "one hundred twenty-eight million, seven hundred thirty-one thousand, eighty-one".