19666681387919 has 8 divisors (see below), whose sum is σ = 20708742582000. Its totient is φ = 18625317463872.

The previous prime is 19666681387849. The next prime is 19666681387921. The reversal of 19666681387919 is 91978318666691.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19666681387919 - 2³⁶ = 19597961911183 is a prime.

It is a super-2 number, since 2×19666681387919² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19666681387019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 174259604 + ... + 174372425.

It is an arithmetic number, because the mean of its divisors is an integer number (2588592822750).

Almost surely, 2^{19666681387919} is an apocalyptic number.

19666681387919 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

19666681387919 is a deficient number, since it is larger than the sum of its proper divisors (1042061194081).

19666681387919 is a wasteful number, since it uses less digits than its factorization.

19666681387919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348635017.

The product of its digits is 1269789696, while the sum is 80.

The spelling of 19666681387919 in words is "nineteen trillion, six hundred sixty-six billion, six hundred eighty-one million, three hundred eighty-seven thousand, nine hundred nineteen".