27750577781 has 2 divisors, whose sum is σ = 27750577782. Its totient is φ = 27750577780.

The previous prime is 27750577733. The next prime is 27750577787. The reversal of 27750577781 is 18777505772.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17184588100 + 10565989681 = 131090^2 + 102791^2 .

It is a cyclic number.

It is not a de Polignac number, because 27750577781 - 2¹⁰ = 27750576757 is a prime.

It is a super-2 number, since 2×27750577781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27750577787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13875288890 + 13875288891.

It is an arithmetic number, because the mean of its divisors is an integer number (13875288891).

Almost surely, 2^27750577781 is an apocalyptic number.

It is an amenable number.

27750577781 is a deficient number, since it is larger than the sum of its proper divisors (1).

27750577781 is an equidigital number, since it uses as much as digits as its factorization.

27750577781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6722800, while the sum is 56.

The spelling of 27750577781 in words is "twenty-seven billion, seven hundred fifty million, five hundred seventy-seven thousand, seven hundred eighty-one".