520347721 has 2 divisors, whose sum is σ = 520347722. Its totient is φ = 520347720.

The previous prime is 520347697. The next prime is 520347749. The reversal of 520347721 is 127743025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 394459321 + 125888400 = 19861^2 + 11220^2 .

It is a cyclic number.

It is not a de Polignac number, because 520347721 - 2²⁵ = 486793289 is a prime.

It is not a weakly prime, because it can be changed into another prime (520348721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260173860 + 260173861.

It is an arithmetic number, because the mean of its divisors is an integer number (260173861).

Almost surely, 2^520347721 is an apocalyptic number.

It is an amenable number.

520347721 is a deficient number, since it is larger than the sum of its proper divisors (1).

520347721 is an equidigital number, since it uses as much as digits as its factorization.

520347721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11760, while the sum is 31.

The square root of 520347721 is about 22811.1315151178. The cubic root of 520347721 is about 804.3243541877.

The spelling of 520347721 in words is "five hundred twenty million, three hundred forty-seven thousand, seven hundred twenty-one".