26516543385581 has 2 divisors, whose sum is σ = 26516543385582. Its totient is φ = 26516543385580.

The previous prime is 26516543385547. The next prime is 26516543385583. The reversal of 26516543385581 is 18558334561562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24713724264100 + 1802819121481 = 4971290^2 + 1342691^2 .

It is a cyclic number.

It is not a de Polignac number, because 26516543385581 - 2⁴² = 22118496874477 is a prime.

It is a super-2 number, since 2×26516543385581² (a number of 28 digits) contains 22 as substring.

Together with 26516543385583, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26516543385583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13258271692790 + 13258271692791.

It is an arithmetic number, because the mean of its divisors is an integer number (13258271692791).

Almost surely, 2^{26516543385581} is an apocalyptic number.

It is an amenable number.

26516543385581 is a deficient number, since it is larger than the sum of its proper divisors (1).

26516543385581 is an equidigital number, since it uses as much as digits as its factorization.

26516543385581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680000, while the sum is 62.

The spelling of 26516543385581 in words is "twenty-six trillion, five hundred sixteen billion, five hundred forty-three million, three hundred eighty-five thousand, five hundred eighty-one".