778772321 has 2 divisors, whose sum is σ = 778772322. Its totient is φ = 778772320.

The previous prime is 778772303. The next prime is 778772333. The reversal of 778772321 is 123277877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 602015296 + 176757025 = 24536^2 + 13295^2 .

It is an emirp because it is prime and its reverse (123277877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 778772321 - 2¹⁸ = 778510177 is a prime.

It is not a weakly prime, because it can be changed into another prime (778772221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389386160 + 389386161.

It is an arithmetic number, because the mean of its divisors is an integer number (389386161).

Almost surely, 2^778772321 is an apocalyptic number.

It is an amenable number.

778772321 is a deficient number, since it is larger than the sum of its proper divisors (1).

778772321 is an equidigital number, since it uses as much as digits as its factorization.

778772321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 230496, while the sum is 44.

The square root of 778772321 is about 27906.4924524742. The cubic root of 778772321 is about 920.0332065046.

It can be divided in two parts, 7787 and 72321, that added together give a palindrome (80108).

The spelling of 778772321 in words is "seven hundred seventy-eight million, seven hundred seventy-two thousand, three hundred twenty-one".