999998855171 has 2 divisors, whose sum is σ = 999998855172. Its totient is φ = 999998855170.

The previous prime is 999998855159. The next prime is 999998855269. The reversal of 999998855171 is 171558899999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999998855171 - 2²² = 999994660867 is a prime.

It is not a weakly prime, because it can be changed into another prime (999998855111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999427585 + 499999427586.

It is an arithmetic number, because the mean of its divisors is an integer number (499999427586).

Almost surely, 2^999998855171 is an apocalyptic number.

999998855171 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998855171 is an equidigital number, since it uses as much as digits as its factorization.

999998855171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 661348800, while the sum is 80.

The spelling of 999998855171 in words is "nine hundred ninety-nine billion, nine hundred ninety-eight million, eight hundred fifty-five thousand, one hundred seventy-one".