520720643 has 4 divisors (see below), whose sum is σ = 521490480. Its totient is φ = 519950808.

The previous prime is 520720637. The next prime is 520720649. The reversal of 520720643 is 346027025.

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

It is an interprime number because it is at equal distance from previous prime (520720637) and next prime (520720649).

It is a cyclic number.

It is not a de Polignac number, because 520720643 - 2⁶ = 520720579 is a prime.

It is a super-2 number, since 2×520720643² = 542299976092666898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (520720649) 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, 383903 + ... + 385256.

It is an arithmetic number, because the mean of its divisors is an integer number (130372620).

Almost surely, 2^520720643 is an apocalyptic number.

520720643 is a deficient number, since it is larger than the sum of its proper divisors (769837).

520720643 is an equidigital number, since it uses as much as digits as its factorization.

520720643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 769836.

The product of its (nonzero) digits is 10080, while the sum is 29.

The square root of 520720643 is about 22819.3041743170. The cubic root of 520720643 is about 804.5164556148.

Adding to 520720643 its reverse (346027025), we get a palindrome (866747668).

The spelling of 520720643 in words is "five hundred twenty million, seven hundred twenty thousand, six hundred forty-three".