27975977657 has 2 divisors, whose sum is σ = 27975977658. Its totient is φ = 27975977656.

The previous prime is 27975977629. The next prime is 27975977671. The reversal of 27975977657 is 75677957972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25963199161 + 2012778496 = 161131^2 + 44864^2 .

It is a cyclic number.

It is not a de Polignac number, because 27975977657 - 2⁸ = 27975977401 is a prime.

It is not a weakly prime, because it can be changed into another prime (27975977857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13987988828 + 13987988829.

It is an arithmetic number, because the mean of its divisors is an integer number (13987988829).

Almost surely, 2^27975977657 is an apocalyptic number.

It is an amenable number.

27975977657 is a deficient number, since it is larger than the sum of its proper divisors (1).

27975977657 is an equidigital number, since it uses as much as digits as its factorization.

27975977657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408410100, while the sum is 71.

The spelling of 27975977657 in words is "twenty-seven billion, nine hundred seventy-five million, nine hundred seventy-seven thousand, six hundred fifty-seven".