27750431561 has 2 divisors, whose sum is σ = 27750431562. Its totient is φ = 27750431560.

The previous prime is 27750431503. The next prime is 27750431591. The reversal of 27750431561 is 16513405772.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27730575625 + 19855936 = 166525^2 + 4456^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27750431561 is a prime.

It is not a weakly prime, because it can be changed into another prime (27750431591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13875215780 + 13875215781.

It is an arithmetic number, because the mean of its divisors is an integer number (13875215781).

Almost surely, 2^27750431561 is an apocalyptic number.

It is an amenable number.

27750431561 is a deficient number, since it is larger than the sum of its proper divisors (1).

27750431561 is an equidigital number, since it uses as much as digits as its factorization.

27750431561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 176400, while the sum is 41.

The spelling of 27750431561 in words is "twenty-seven billion, seven hundred fifty million, four hundred thirty-one thousand, five hundred sixty-one".