20487989165971 has 2 divisors, whose sum is σ = 20487989165972. Its totient is φ = 20487989165970.

The previous prime is 20487989165953. The next prime is 20487989165993. The reversal of 20487989165971 is 17956198978402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20487989165971 - 2²¹ = 20487987068819 is a prime.

It is not a weakly prime, because it can be changed into another prime (20487989175971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10243994582985 + 10243994582986.

It is an arithmetic number, because the mean of its divisors is an integer number (10243994582986).

Almost surely, 2^{20487989165971} is an apocalyptic number.

20487989165971 is a deficient number, since it is larger than the sum of its proper divisors (1).

20487989165971 is an equidigital number, since it uses as much as digits as its factorization.

20487989165971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 548674560, while the sum is 76.

The spelling of 20487989165971 in words is "twenty trillion, four hundred eighty-seven billion, nine hundred eighty-nine million, one hundred sixty-five thousand, nine hundred seventy-one".