27728587657 has 2 divisors, whose sum is σ = 27728587658. Its totient is φ = 27728587656.

The previous prime is 27728587589. The next prime is 27728587703. The reversal of 27728587657 is 75678582772.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25236181881 + 2492405776 = 158859^2 + 49924^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27728587657 is a prime.

It is not a weakly prime, because it can be changed into another prime (27728587357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13864293828 + 13864293829.

It is an arithmetic number, because the mean of its divisors is an integer number (13864293829).

Almost surely, 2^27728587657 is an apocalyptic number.

It is an amenable number.

27728587657 is a deficient number, since it is larger than the sum of its proper divisors (1).

27728587657 is an equidigital number, since it uses as much as digits as its factorization.

27728587657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 92198400, while the sum is 64.

The spelling of 27728587657 in words is "twenty-seven billion, seven hundred twenty-eight million, five hundred eighty-seven thousand, six hundred fifty-seven".