20001666868537 has 2 divisors, whose sum is σ = 20001666868538. Its totient is φ = 20001666868536.

The previous prime is 20001666868523. The next prime is 20001666868577. The reversal of 20001666868537 is 73586866610002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14297503689616 + 5704163178921 = 3781204^2 + 2388339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20001666868537 is a prime.

It is not a weakly prime, because it can be changed into another prime (20001666868577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000833434268 + 10000833434269.

It is an arithmetic number, because the mean of its divisors is an integer number (10000833434269).

Almost surely, 2^{20001666868537} is an apocalyptic number.

It is an amenable number.

20001666868537 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001666868537 is an equidigital number, since it uses as much as digits as its factorization.

20001666868537 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17418240, while the sum is 58.

The spelling of 20001666868537 in words is "twenty trillion, one billion, six hundred sixty-six million, eight hundred sixty-eight thousand, five hundred thirty-seven".