520663861 has 4 divisors (see below), whose sum is σ = 520728012. Its totient is φ = 520599712.

The previous prime is 520663763. The next prime is 520663921. The reversal of 520663861 is 168366025.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 198640836 + 322023025 = 14094^2 + 17945^2 .

It is a cyclic number.

It is not a de Polignac number, because 520663861 - 2⁷ = 520663733 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 520663861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520664861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17776 + ... + 36841.

It is an arithmetic number, because the mean of its divisors is an integer number (130182003).

Almost surely, 2^520663861 is an apocalyptic number.

It is an amenable number.

520663861 is a deficient number, since it is larger than the sum of its proper divisors (64151).

520663861 is an equidigital number, since it uses as much as digits as its factorization.

520663861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64150.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 520663861 is about 22818.0599745027. The cubic root of 520663861 is about 804.4872117105.

The spelling of 520663861 in words is "five hundred twenty million, six hundred sixty-three thousand, eight hundred sixty-one".