128320817 has 2 divisors, whose sum is σ = 128320818. Its totient is φ = 128320816.

The previous prime is 128320807. The next prime is 128320831. The reversal of 128320817 is 718023821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119224561 + 9096256 = 10919^2 + 3016^2 .

It is a cyclic number.

It is not a de Polignac number, because 128320817 - 2⁸ = 128320561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128320807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64160408 + 64160409.

It is an arithmetic number, because the mean of its divisors is an integer number (64160409).

Almost surely, 2^128320817 is an apocalyptic number.

It is an amenable number.

128320817 is a deficient number, since it is larger than the sum of its proper divisors (1).

128320817 is an equidigital number, since it uses as much as digits as its factorization.

128320817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 128320817 is about 11327.8778683388. The cubic root of 128320817 is about 504.3891146081.

The spelling of 128320817 in words is "one hundred twenty-eight million, three hundred twenty thousand, eight hundred seventeen".