520721816 has 8 divisors (see below), whose sum is σ = 976353420. Its totient is φ = 260360904.

The previous prime is 520721807. The next prime is 520721819. The reversal of 520721816 is 618127025.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520721819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32545106 + ... + 32545121.

Almost surely, 2^520721816 is an apocalyptic number.

It is an amenable number.

520721816 is a deficient number, since it is larger than the sum of its proper divisors (455631604).

520721816 is a wasteful number, since it uses less digits than its factorization.

520721816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65090233 (or 65090229 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 520721816 is about 22819.3298762256. The cubic root of 520721816 is about 804.5170597117.

The spelling of 520721816 in words is "five hundred twenty million, seven hundred twenty-one thousand, eight hundred sixteen".