20001971765989 has 2 divisors, whose sum is σ = 20001971765990. Its totient is φ = 20001971765988.

The previous prime is 20001971765959. The next prime is 20001971766019. The reversal of 20001971765989 is 98956717910002.

It is a balanced prime because it is at equal distance from previous prime (20001971765959) and next prime (20001971766019).

It can be written as a sum of positive squares in only one way, i.e., 15472949343489 + 4529022422500 = 3933567^2 + 2128150^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001971765989 - 2⁷ = 20001971765861 is a prime.

It is a super-2 number, since 2×20001971765989² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20001971765989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001971765929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000985882994 + 10000985882995.

It is an arithmetic number, because the mean of its divisors is an integer number (10000985882995).

Almost surely, 2^{20001971765989} is an apocalyptic number.

It is an amenable number.

20001971765989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001971765989 is an equidigital number, since it uses as much as digits as its factorization.

20001971765989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17146080, while the sum is 64.

The spelling of 20001971765989 in words is "twenty trillion, one billion, nine hundred seventy-one million, seven hundred sixty-five thousand, nine hundred eighty-nine".