520868809 has 2 divisors, whose sum is σ = 520868810. Its totient is φ = 520868808.

The previous prime is 520868807. The next prime is 520868857. The reversal of 520868809 is 908868025.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 325008784 + 195860025 = 18028^2 + 13995^2 .

It is a cyclic number.

It is not a de Polignac number, because 520868809 - 2¹ = 520868807 is a prime.

Together with 520868807, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (520868801) 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, 260434404 + 260434405.

It is an arithmetic number, because the mean of its divisors is an integer number (260434405).

Almost surely, 2^520868809 is an apocalyptic number.

It is an amenable number.

520868809 is a deficient number, since it is larger than the sum of its proper divisors (1).

520868809 is an equidigital number, since it uses as much as digits as its factorization.

520868809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 276480, while the sum is 46.

The square root of 520868809 is about 22822.5504490624. The cubic root of 520868809 is about 804.5927541591.

The spelling of 520868809 in words is "five hundred twenty million, eight hundred sixty-eight thousand, eight hundred nine".