7781688289 has 2 divisors, whose sum is σ = 7781688290. Its totient is φ = 7781688288.

The previous prime is 7781688287. The next prime is 7781688353. The reversal of 7781688289 is 9828861877.

It is an a-pointer prime, because the next prime (7781688353) can be obtained adding 7781688289 to its sum of digits (64).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7753683025 + 28005264 = 88055^2 + 5292^2 .

It is a cyclic number.

It is not a de Polignac number, because 7781688289 - 2¹ = 7781688287 is a prime.

Together with 7781688287, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 7781688289.

It is not a weakly prime, because it can be changed into another prime (7781688281) 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, 3890844144 + 3890844145.

It is an arithmetic number, because the mean of its divisors is an integer number (3890844145).

Almost surely, 2^7781688289 is an apocalyptic number.

It is an amenable number.

7781688289 is a deficient number, since it is larger than the sum of its proper divisors (1).

7781688289 is an equidigital number, since it uses as much as digits as its factorization.

7781688289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21676032, while the sum is 64.

The square root of 7781688289 is about 88213.8780974967. The cubic root of 7781688289 is about 1981.6393158604.

The spelling of 7781688289 in words is "seven billion, seven hundred eighty-one million, six hundred eighty-eight thousand, two hundred eighty-nine".