77278923809 has 2 divisors, whose sum is σ = 77278923810. Its totient is φ = 77278923808.

The previous prime is 77278923803. The next prime is 77278923811. The reversal of 77278923809 is 90832987277.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75530429584 + 1748494225 = 274828^2 + 41815^2 .

It is an emirp because it is prime and its reverse (90832987277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77278923809 - 2³⁶ = 8559447073 is a prime.

Together with 77278923811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77278923803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38639461904 + 38639461905.

It is an arithmetic number, because the mean of its divisors is an integer number (38639461905).

Almost surely, 2^77278923809 is an apocalyptic number.

It is an amenable number.

77278923809 is a deficient number, since it is larger than the sum of its proper divisors (1).

77278923809 is an equidigital number, since it uses as much as digits as its factorization.

77278923809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21337344, while the sum is 62.

The spelling of 77278923809 in words is "seventy-seven billion, two hundred seventy-eight million, nine hundred twenty-three thousand, eight hundred nine".