520222721 has 2 divisors, whose sum is σ = 520222722. Its totient is φ = 520222720.

The previous prime is 520222567. The next prime is 520222723. The reversal of 520222721 is 127222025.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 435306496 + 84916225 = 20864^2 + 9215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-520222721 is a prime.

It is a Sophie Germain prime.

Together with 520222723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (520222723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260111360 + 260111361.

It is an arithmetic number, because the mean of its divisors is an integer number (260111361).

Almost surely, 2^520222721 is an apocalyptic number.

It is an amenable number.

520222721 is a deficient number, since it is larger than the sum of its proper divisors (1).

520222721 is an equidigital number, since it uses as much as digits as its factorization.

520222721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 520222721 is about 22808.3914601622. The cubic root of 520222721 is about 804.2599430308.

Adding to 520222721 its reverse (127222025), we get a palindrome (647444746).

The spelling of 520222721 in words is "five hundred twenty million, two hundred twenty-two thousand, seven hundred twenty-one".