77843279909 has 2 divisors, whose sum is σ = 77843279910. Its totient is φ = 77843279908.

The previous prime is 77843279887. The next prime is 77843279929. The reversal of 77843279909 is 90997234877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57286029025 + 20557250884 = 239345^2 + 143378^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77843279909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77843279929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38921639954 + 38921639955.

It is an arithmetic number, because the mean of its divisors is an integer number (38921639955).

Almost surely, 2^77843279909 is an apocalyptic number.

It is an amenable number.

77843279909 is a deficient number, since it is larger than the sum of its proper divisors (1).

77843279909 is an equidigital number, since it uses as much as digits as its factorization.

77843279909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48009024, while the sum is 65.

The spelling of 77843279909 in words is "seventy-seven billion, eight hundred forty-three million, two hundred seventy-nine thousand, nine hundred nine".