1999172112071 has 2 divisors, whose sum is σ = 1999172112072. Its totient is φ = 1999172112070.

The previous prime is 1999172112013. The next prime is 1999172112073. The reversal of 1999172112071 is 1702112719991.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1999172112071 is a prime.

Together with 1999172112073, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999172112073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999586056035 + 999586056036.

It is an arithmetic number, because the mean of its divisors is an integer number (999586056036).

Almost surely, 2^{1999172112071} is an apocalyptic number.

1999172112071 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999172112071 is an equidigital number, since it uses as much as digits as its factorization.

1999172112071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 142884, while the sum is 50.

The spelling of 1999172112071 in words is "one trillion, nine hundred ninety-nine billion, one hundred seventy-two million, one hundred twelve thousand, seventy-one".