19987131182917 has 2 divisors, whose sum is σ = 19987131182918. Its totient is φ = 19987131182916.

The previous prime is 19987131182867. The next prime is 19987131182969. The reversal of 19987131182917 is 71928113178991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19966830917476 + 20300265441 = 4468426^2 + 142479^2 .

It is a cyclic number.

It is not a de Polignac number, because 19987131182917 - 2¹¹ = 19987131180869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19987131182017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9993565591458 + 9993565591459.

It is an arithmetic number, because the mean of its divisors is an integer number (9993565591459).

Almost surely, 2^{19987131182917} is an apocalyptic number.

It is an amenable number.

19987131182917 is a deficient number, since it is larger than the sum of its proper divisors (1).

19987131182917 is an equidigital number, since it uses as much as digits as its factorization.

19987131182917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13716864, while the sum is 67.

The spelling of 19987131182917 in words is "nineteen trillion, nine hundred eighty-seven billion, one hundred thirty-one million, one hundred eighty-two thousand, nine hundred seventeen".