21647109728963 has 2 divisors, whose sum is σ = 21647109728964. Its totient is φ = 21647109728962.

The previous prime is 21647109728947. The next prime is 21647109728983. The reversal of 21647109728963 is 36982790174612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21647109728963 - 2⁴ = 21647109728947 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21647109728963.

It is not a weakly prime, because it can be changed into another prime (21647109728983) 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, 10823554864481 + 10823554864482.

It is an arithmetic number, because the mean of its divisors is an integer number (10823554864482).

Almost surely, 2^{21647109728963} is an apocalyptic number.

21647109728963 is a deficient number, since it is larger than the sum of its proper divisors (1).

21647109728963 is an equidigital number, since it uses as much as digits as its factorization.

21647109728963 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54867456, while the sum is 65.

The spelling of 21647109728963 in words is "twenty-one trillion, six hundred forty-seven billion, one hundred nine million, seven hundred twenty-eight thousand, nine hundred sixty-three".