21100347878647 has 2 divisors, whose sum is σ = 21100347878648. Its totient is φ = 21100347878646.

The previous prime is 21100347878587. The next prime is 21100347878681. The reversal of 21100347878647 is 74687874300112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100347878647 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21100347878591 and 21100347878600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100347878147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550173939323 + 10550173939324.

It is an arithmetic number, because the mean of its divisors is an integer number (10550173939324).

Almost surely, 2^{21100347878647} is an apocalyptic number.

21100347878647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100347878647 is an equidigital number, since it uses as much as digits as its factorization.

21100347878647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12644352, while the sum is 58.

The spelling of 21100347878647 in words is "twenty-one trillion, one hundred billion, three hundred forty-seven million, eight hundred seventy-eight thousand, six hundred forty-seven".