520721720 has 64 divisors (see below), whose sum is σ = 1210187520. Its totient is φ = 201498624.

The previous prime is 520721699. The next prime is 520721723. The reversal of 520721720 is 27127025.

It is a super-2 number, since 2×520721720² = 542302219359516800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 520721720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520721723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 284729 + ... + 286551.

It is an arithmetic number, because the mean of its divisors is an integer number (18909180).

Almost surely, 2^520721720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 520721720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (605093760).

520721720 is an abundant number, since it is smaller than the sum of its proper divisors (689465800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

520721720 is a wasteful number, since it uses less digits than its factorization.

520721720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2064 (or 2060 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 520721720 is about 22819.3277727456. The cubic root of 520721720 is about 804.5170102716.

Adding to 520721720 its reverse (27127025), we get a palindrome (547848745).

The spelling of 520721720 in words is "five hundred twenty million, seven hundred twenty-one thousand, seven hundred twenty".