520661909 has 2 divisors, whose sum is σ = 520661910. Its totient is φ = 520661908.

The previous prime is 520661899. The next prime is 520661923. The reversal of 520661909 is 909166025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499299025 + 21362884 = 22345^2 + 4622^2 .

It is a cyclic number.

It is not a de Polignac number, because 520661909 - 2⁸ = 520661653 is a prime.

It is equal to p_27385562 and since 520661909 and 27385562 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260330954 + 260330955.

It is an arithmetic number, because the mean of its divisors is an integer number (260330955).

Almost surely, 2^520661909 is an apocalyptic number.

It is an amenable number.

520661909 is a deficient number, since it is larger than the sum of its proper divisors (1).

520661909 is an equidigital number, since it uses as much as digits as its factorization.

520661909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 520661909 is about 22818.0172013258. The cubic root of 520661909 is about 804.4862063524.

The spelling of 520661909 in words is "five hundred twenty million, six hundred sixty-one thousand, nine hundred nine".