128320767748661 has 2 divisors, whose sum is σ = 128320767748662. Its totient is φ = 128320767748660.

The previous prime is 128320767748603. The next prime is 128320767748673. The reversal of 128320767748661 is 166847767023821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90555207602500 + 37765560146161 = 9516050^2 + 6145369^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128320767748661 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 128320767748591 and 128320767748600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128320767748561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64160383874330 + 64160383874331.

It is an arithmetic number, because the mean of its divisors is an integer number (64160383874331).

Almost surely, 2^{128320767748661} is an apocalyptic number.

It is an amenable number.

128320767748661 is a deficient number, since it is larger than the sum of its proper divisors (1).

128320767748661 is an equidigital number, since it uses as much as digits as its factorization.

128320767748661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 227598336, while the sum is 68.

The spelling of 128320767748661 in words is "one hundred twenty-eight trillion, three hundred twenty billion, seven hundred sixty-seven million, seven hundred forty-eight thousand, six hundred sixty-one".