780856406809 has 2 divisors, whose sum is σ = 780856406810. Its totient is φ = 780856406808.

The previous prime is 780856406791. The next prime is 780856406839. The reversal of 780856406809 is 908604658087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 410618232025 + 370238174784 = 640795^2 + 608472^2 .

It is a cyclic number.

It is not a de Polignac number, because 780856406809 - 2¹³ = 780856398617 is a prime.

It is not a weakly prime, because it can be changed into another prime (780856406839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390428203404 + 390428203405.

It is an arithmetic number, because the mean of its divisors is an integer number (390428203405).

Almost surely, 2^780856406809 is an apocalyptic number.

It is an amenable number.

780856406809 is a deficient number, since it is larger than the sum of its proper divisors (1).

780856406809 is an equidigital number, since it uses as much as digits as its factorization.

780856406809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23224320, while the sum is 61.

The spelling of 780856406809 in words is "seven hundred eighty billion, eight hundred fifty-six million, four hundred six thousand, eight hundred nine".