21847865188871 has 2 divisors, whose sum is σ = 21847865188872. Its totient is φ = 21847865188870.

The previous prime is 21847865188763. The next prime is 21847865188907. The reversal of 21847865188871 is 17888156874812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21847865188871 - 2³⁸ = 21572987281927 is a prime.

It is a super-2 number, since 2×21847865188871² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21847862188871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923932594435 + 10923932594436.

It is an arithmetic number, because the mean of its divisors is an integer number (10923932594436).

Almost surely, 2^{21847865188871} is an apocalyptic number.

21847865188871 is a deficient number, since it is larger than the sum of its proper divisors (1).

21847865188871 is an equidigital number, since it uses as much as digits as its factorization.

21847865188871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 385351680, while the sum is 74.

The spelling of 21847865188871 in words is "twenty-one trillion, eight hundred forty-seven billion, eight hundred sixty-five million, one hundred eighty-eight thousand, eight hundred seventy-one".