999998656123807 has 2 divisors, whose sum is σ = 999998656123808. Its totient is φ = 999998656123806.

The previous prime is 999998656123777. The next prime is 999998656123919. The reversal of 999998656123807 is 708321656899999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999998656123807 - 2⁷ = 999998656123679 is a prime.

It is a super-2 number, since 2×999998656123807² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999998656123007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999328061903 + 499999328061904.

It is an arithmetic number, because the mean of its divisors is an integer number (499999328061904).

Almost surely, 2^{999998656123807} is an apocalyptic number.

999998656123807 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998656123807 is an equidigital number, since it uses as much as digits as its factorization.

999998656123807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28570268160, while the sum is 91.

The spelling of 999998656123807 in words is "nine hundred ninety-nine trillion, nine hundred ninety-eight billion, six hundred fifty-six million, one hundred twenty-three thousand, eight hundred seven".