520991820 has 144 divisors (see below), whose sum is σ = 1637764128. Its totient is φ = 133954560.

The previous prime is 520991803. The next prime is 520991831. The reversal of 520991820 is 28199025.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 912135 + ... + 912705.

It is an arithmetic number, because the mean of its divisors is an integer number (11373362).

Almost surely, 2^520991820 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 520991820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818882064).

520991820 is an abundant number, since it is smaller than the sum of its proper divisors (1116772308).

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

520991820 is a wasteful number, since it uses less digits than its factorization.

520991820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760 (or 755 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 520991820 is about 22825.2452341700. The cubic root of 520991820 is about 804.6560880653.

The spelling of 520991820 in words is "five hundred twenty million, nine hundred ninety-one thousand, eight hundred twenty".