128997811 has 2 divisors, whose sum is σ = 128997812. Its totient is φ = 128997810.

The previous prime is 128997797. The next prime is 128997833. The reversal of 128997811 is 118799821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128997811 - 2⁵ = 128997779 is a prime.

It is not a weakly prime, because it can be changed into another prime (128997511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64498905 + 64498906.

It is an arithmetic number, because the mean of its divisors is an integer number (64498906).

Almost surely, 2^128997811 is an apocalyptic number.

128997811 is a deficient number, since it is larger than the sum of its proper divisors (1).

128997811 is an equidigital number, since it uses as much as digits as its factorization.

128997811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 46.

The square root of 128997811 is about 11357.7203258400. The cubic root of 128997811 is about 505.2745766884.

The spelling of 128997811 in words is "one hundred twenty-eight million, nine hundred ninety-seven thousand, eight hundred eleven".