21791840817139 has 2 divisors, whose sum is σ = 21791840817140. Its totient is φ = 21791840817138.

The previous prime is 21791840817137. The next prime is 21791840817161. The reversal of 21791840817139 is 93171804819712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21791840817139 - 2¹ = 21791840817137 is a prime.

It is a super-2 number, since 2×21791840817139² (a number of 27 digits) contains 22 as substring.

Together with 21791840817137, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21791840817137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10895920408569 + 10895920408570.

It is an arithmetic number, because the mean of its divisors is an integer number (10895920408570).

Almost surely, 2^{21791840817139} is an apocalyptic number.

21791840817139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21791840817139 is an equidigital number, since it uses as much as digits as its factorization.

21791840817139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6096384, while the sum is 61.

The spelling of 21791840817139 in words is "twenty-one trillion, seven hundred ninety-one billion, eight hundred forty million, eight hundred seventeen thousand, one hundred thirty-nine".