19971364643999 has 16 divisors (see below), whose sum is σ = 20864004986880. Its totient is φ = 19080756266880.

The previous prime is 19971364643987. The next prime is 19971364644013. The reversal of 19971364643999 is 99934646317991.

It is not a de Polignac number, because 19971364643999 - 2³⁶ = 19902645167263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19971364643299) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 179673962 + ... + 179785080.

It is an arithmetic number, because the mean of its divisors is an integer number (1304000311680).

Almost surely, 2^{19971364643999} is an apocalyptic number.

19971364643999 is a deficient number, since it is larger than the sum of its proper divisors (892640342881).

19971364643999 is a wasteful number, since it uses less digits than its factorization.

19971364643999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120190.

The product of its digits is 2142770112, while the sum is 80.

The spelling of 19971364643999 in words is "nineteen trillion, nine hundred seventy-one billion, three hundred sixty-four million, six hundred forty-three thousand, nine hundred ninety-nine".