27766005581 has 2 divisors, whose sum is σ = 27766005582. Its totient is φ = 27766005580.

The previous prime is 27766005577. The next prime is 27766005583. The reversal of 27766005581 is 18550066772.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17953320100 + 9812685481 = 133990^2 + 99059^2 .

It is a cyclic number.

It is not a de Polignac number, because 27766005581 - 2² = 27766005577 is a prime.

It is a super-2 number, since 2×27766005581² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 27766005583, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27766005583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13883002790 + 13883002791.

It is an arithmetic number, because the mean of its divisors is an integer number (13883002791).

Almost surely, 2^27766005581 is an apocalyptic number.

It is an amenable number.

27766005581 is a deficient number, since it is larger than the sum of its proper divisors (1).

27766005581 is an equidigital number, since it uses as much as digits as its factorization.

27766005581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 705600, while the sum is 47.

The spelling of 27766005581 in words is "twenty-seven billion, seven hundred sixty-six million, five thousand, five hundred eighty-one".