520749021 has 8 divisors (see below), whose sum is σ = 747742240. Its totient is φ = 320460912.

The previous prime is 520749013. The next prime is 520749023. The reversal of 520749021 is 120947025.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 520749021 - 2³ = 520749013 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 520749021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520749023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6676231 + ... + 6676308.

It is an arithmetic number, because the mean of its divisors is an integer number (93467780).

Almost surely, 2^520749021 is an apocalyptic number.

It is an amenable number.

520749021 is a deficient number, since it is larger than the sum of its proper divisors (226993219).

520749021 is a wasteful number, since it uses less digits than its factorization.

520749021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13352555.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 520749021 is about 22819.9259639465. The cubic root of 520749021 is about 804.5310700750.

The spelling of 520749021 in words is "five hundred twenty million, seven hundred forty-nine thousand, twenty-one".