77128069 has 2 divisors, whose sum is σ = 77128070. Its totient is φ = 77128068.

The previous prime is 77128067. The next prime is 77128097. The reversal of 77128069 is 96082177.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75463969 + 1664100 = 8687^2 + 1290^2 .

It is an emirp because it is prime and its reverse (96082177) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77128069 - 2¹ = 77128067 is a prime.

It is a super-2 number, since 2×77128069² = 11897478055337522, which contains 22 as substring.

Together with 77128067, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77128067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38564034 + 38564035.

It is an arithmetic number, because the mean of its divisors is an integer number (38564035).

Almost surely, 2^77128069 is an apocalyptic number.

It is an amenable number.

77128069 is a deficient number, since it is larger than the sum of its proper divisors (1).

77128069 is an equidigital number, since it uses as much as digits as its factorization.

77128069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 77128069 is about 8782.2587641221. The cubic root of 77128069 is about 425.6678202035.

The spelling of 77128069 in words is "seventy-seven million, one hundred twenty-eight thousand, sixty-nine".