778999999 has 2 divisors, whose sum is σ = 779000000. Its totient is φ = 778999998.

The previous prime is 778999967. The next prime is 779000029. The reversal of 778999999 is 999999877.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 778999999 - 2⁵ = 778999967 is a prime.

778999999 is a modest number, since divided by 99999 gives 7789 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (778999939) 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, 389499999 + 389500000.

It is an arithmetic number, because the mean of its divisors is an integer number (389500000).

Almost surely, 2^778999999 is an apocalyptic number.

778999999 is a deficient number, since it is larger than the sum of its proper divisors (1).

778999999 is an equidigital number, since it uses as much as digits as its factorization.

778999999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 208324872, while the sum is 76.

The square root of 778999999 is about 27910.5714559914. The cubic root of 778999999 is about 920.1228565452.

The spelling of 778999999 in words is "seven hundred seventy-eight million, nine hundred ninety-nine thousand, nine hundred ninety-nine".