520663921 has 2 divisors, whose sum is σ = 520663922. Its totient is φ = 520663920.

The previous prime is 520663763. The next prime is 520663931. The reversal of 520663921 is 129366025.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 468246321 + 52417600 = 21639^2 + 7240^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-520663921 is a prime.

It is not a weakly prime, because it can be changed into another prime (520663931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260331960 + 260331961.

It is an arithmetic number, because the mean of its divisors is an integer number (260331961).

Almost surely, 2^520663921 is an apocalyptic number.

It is an amenable number.

520663921 is a deficient number, since it is larger than the sum of its proper divisors (1).

520663921 is an equidigital number, since it uses as much as digits as its factorization.

520663921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 520663921 is about 22818.0612892507. The cubic root of 520663921 is about 804.4872426129.

The spelling of 520663921 in words is "five hundred twenty million, six hundred sixty-three thousand, nine hundred twenty-one".