27642654664561 has 2 divisors, whose sum is σ = 27642654664562. Its totient is φ = 27642654664560.

The previous prime is 27642654664523. The next prime is 27642654664571. The reversal of 27642654664561 is 16546645624672.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15462833862961 + 12179820801600 = 3932281^2 + 3489960^2 .

It is a cyclic number.

It is not a de Polignac number, because 27642654664561 - 2²⁵ = 27642621110129 is a prime.

It is a super-3 number, since 3×27642654664561³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 27642654664493 and 27642654664502.

It is not a weakly prime, because it can be changed into another prime (27642654664571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13821327332280 + 13821327332281.

It is an arithmetic number, because the mean of its divisors is an integer number (13821327332281).

Almost surely, 2^{27642654664561} is an apocalyptic number.

It is an amenable number.

27642654664561 is a deficient number, since it is larger than the sum of its proper divisors (1).

27642654664561 is an equidigital number, since it uses as much as digits as its factorization.

27642654664561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 348364800, while the sum is 64.

The spelling of 27642654664561 in words is "twenty-seven trillion, six hundred forty-two billion, six hundred fifty-four million, six hundred sixty-four thousand, five hundred sixty-one".