77809342657 has 2 divisors, whose sum is σ = 77809342658. Its totient is φ = 77809342656.

The previous prime is 77809342571. The next prime is 77809342673. The reversal of 77809342657 is 75624390877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71397977616 + 6411365041 = 267204^2 + 80071^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77809342657 is a prime.

It is not a weakly prime, because it can be changed into another prime (77809352657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38904671328 + 38904671329.

It is an arithmetic number, because the mean of its divisors is an integer number (38904671329).

Almost surely, 2^77809342657 is an apocalyptic number.

It is an amenable number.

77809342657 is a deficient number, since it is larger than the sum of its proper divisors (1).

77809342657 is an equidigital number, since it uses as much as digits as its factorization.

77809342657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17781120, while the sum is 58.

The spelling of 77809342657 in words is "seventy-seven billion, eight hundred nine million, three hundred forty-two thousand, six hundred fifty-seven".