520648721 has 2 divisors, whose sum is σ = 520648722. Its totient is φ = 520648720.

The previous prime is 520648717. The next prime is 520648741. The reversal of 520648721 is 127846025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 409050625 + 111598096 = 20225^2 + 10564^2 .

It is a cyclic number.

It is not a de Polignac number, because 520648721 - 2² = 520648717 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (520648741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260324360 + 260324361.

It is an arithmetic number, because the mean of its divisors is an integer number (260324361).

Almost surely, 2^520648721 is an apocalyptic number.

It is an amenable number.

520648721 is a deficient number, since it is larger than the sum of its proper divisors (1).

520648721 is an equidigital number, since it uses as much as digits as its factorization.

520648721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 520648721 is about 22817.7282173314. The cubic root of 520648721 is about 804.4794139384.

The spelling of 520648721 in words is "five hundred twenty million, six hundred forty-eight thousand, seven hundred twenty-one".