778448641 has 2 divisors, whose sum is σ = 778448642. Its totient is φ = 778448640.

The previous prime is 778448551. The next prime is 778448669. The reversal of 778448641 is 146844877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 777238641 + 1210000 = 27879^2 + 1100^2 .

It is an emirp because it is prime and its reverse (146844877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 778448641 - 2¹⁷ = 778317569 is a prime.

It is not a weakly prime, because it can be changed into another prime (778443641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389224320 + 389224321.

It is an arithmetic number, because the mean of its divisors is an integer number (389224321).

Almost surely, 2^778448641 is an apocalyptic number.

It is an amenable number.

778448641 is a deficient number, since it is larger than the sum of its proper divisors (1).

778448641 is an equidigital number, since it uses as much as digits as its factorization.

778448641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1204224, while the sum is 49.

The square root of 778448641 is about 27900.6924824457. The cubic root of 778448641 is about 919.9057248230.

The spelling of 778448641 in words is "seven hundred seventy-eight million, four hundred forty-eight thousand, six hundred forty-one".