778374721 has 2 divisors, whose sum is σ = 778374722. Its totient is φ = 778374720.

The previous prime is 778374719. The next prime is 778374799. The reversal of 778374721 is 127473877.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 770839696 + 7535025 = 27764^2 + 2745^2 .

It is a cyclic number.

It is not a de Polignac number, because 778374721 - 2¹ = 778374719 is a prime.

Together with 778374719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (770374721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389187360 + 389187361.

It is an arithmetic number, because the mean of its divisors is an integer number (389187361).

Almost surely, 2^778374721 is an apocalyptic number.

It is an amenable number.

778374721 is a deficient number, since it is larger than the sum of its proper divisors (1).

778374721 is an equidigital number, since it uses as much as digits as its factorization.

778374721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 460992, while the sum is 46.

The square root of 778374721 is about 27899.3677526929. The cubic root of 778374721 is about 919.8766064029.

The spelling of 778374721 in words is "seven hundred seventy-eight million, three hundred seventy-four thousand, seven hundred twenty-one".