513821 has 8 divisors (see below), whose sum is σ = 640704. Its totient is φ = 400320.

The previous prime is 513781. The next prime is 513829. The reversal of 513821 is 128315.

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

It is a cyclic number.

It is not a de Polignac number, because 513821 - 2¹⁰ = 512797 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 513793 and 513802.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 513821.

It is not an unprimeable number, because it can be changed into a prime (513829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3260 + ... + 3413.

It is an arithmetic number, because the mean of its divisors is an integer number (80088).

2⁵¹³⁸²¹ is an apocalyptic number.

It is an amenable number.

513821 is a deficient number, since it is larger than the sum of its proper divisors (126883).

513821 is a wasteful number, since it uses less digits than its factorization.

513821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6691.

The product of its digits is 240, while the sum is 20.

The square root of 513821 is about 716.8130858181. The cubic root of 513821 is about 80.0947315299.

The spelling of 513821 in words is "five hundred thirteen thousand, eight hundred twenty-one".