520725661 has 2 divisors, whose sum is σ = 520725662. Its totient is φ = 520725660.

The previous prime is 520725659. The next prime is 520725677. The reversal of 520725661 is 166527025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 509901561 + 10824100 = 22581^2 + 3290^2 .

It is a cyclic number.

It is not a de Polignac number, because 520725661 - 2¹ = 520725659 is a prime.

Together with 520725659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (520725641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260362830 + 260362831.

It is an arithmetic number, because the mean of its divisors is an integer number (260362831).

Almost surely, 2^520725661 is an apocalyptic number.

It is an amenable number.

520725661 is a deficient number, since it is larger than the sum of its proper divisors (1).

520725661 is an equidigital number, since it uses as much as digits as its factorization.

520725661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 520725661 is about 22819.4141248192. The cubic root of 520725661 is about 804.5190398864.

The spelling of 520725661 in words is "five hundred twenty million, seven hundred twenty-five thousand, six hundred sixty-one".