21963636217997 has 2 divisors, whose sum is σ = 21963636217998. Its totient is φ = 21963636217996.

The previous prime is 21963636217979. The next prime is 21963636218023. The reversal of 21963636217997 is 79971263636912.

Together with previous prime (21963636217979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18545330732041 + 3418305485956 = 4306429^2 + 1848866^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21963636217997 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21963636217997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21963636217927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10981818108998 + 10981818108999.

It is an arithmetic number, because the mean of its divisors is an integer number (10981818108999).

Almost surely, 2^{21963636217997} is an apocalyptic number.

It is an amenable number.

21963636217997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21963636217997 is an equidigital number, since it uses as much as digits as its factorization.

21963636217997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 277766496, while the sum is 71.

The spelling of 21963636217997 in words is "twenty-one trillion, nine hundred sixty-three billion, six hundred thirty-six million, two hundred seventeen thousand, nine hundred ninety-seven".