27775782781 has 2 divisors, whose sum is σ = 27775782782. Its totient is φ = 27775782780.

The previous prime is 27775782763. The next prime is 27775782799. The reversal of 27775782781 is 18728757772.

It is a balanced prime because it is at equal distance from previous prime (27775782763) and next prime (27775782799).

It can be written as a sum of positive squares in only one way, i.e., 18238502500 + 9537280281 = 135050^2 + 97659^2 .

It is a cyclic number.

It is not a de Polignac number, because 27775782781 - 2¹¹ = 27775780733 is a prime.

It is a super-2 number, since 2×27775782781² (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 (27775786781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13887891390 + 13887891391.

It is an arithmetic number, because the mean of its divisors is an integer number (13887891391).

Almost surely, 2^27775782781 is an apocalyptic number.

It is an amenable number.

27775782781 is a deficient number, since it is larger than the sum of its proper divisors (1).

27775782781 is an equidigital number, since it uses as much as digits as its factorization.

27775782781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21512960, while the sum is 61.

The spelling of 27775782781 in words is "twenty-seven billion, seven hundred seventy-five million, seven hundred eighty-two thousand, seven hundred eighty-one".