999998656123777 has 2 divisors, whose sum is σ = 999998656123778. Its totient is φ = 999998656123776.

The previous prime is 999998656123717. The next prime is 999998656123807. The reversal of 999998656123777 is 777321656899999.

999998656123777 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 987767520855361 + 12231135268416 = 31428769^2 + 3497304^2 .

It is a cyclic number.

It is not a de Polignac number, because 999998656123777 - 2²³ = 999998647735169 is a prime.

It is not a weakly prime, because it can be changed into another prime (999998656123717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999328061888 + 499999328061889.

It is an arithmetic number, because the mean of its divisors is an integer number (499999328061889).

Almost surely, 2^{999998656123777} is an apocalyptic number.

It is an amenable number.

999998656123777 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998656123777 is an equidigital number, since it uses as much as digits as its factorization.

999998656123777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174992892480, while the sum is 97.

The spelling of 999998656123777 in words is "nine hundred ninety-nine trillion, nine hundred ninety-eight billion, six hundred fifty-six million, one hundred twenty-three thousand, seven hundred seventy-seven".