4821 has 4 divisors (see below), whose sum is σ = 6432. Its totient is φ = 3212.

The previous prime is 4817. The next prime is 4831. The reversal of 4821 is 1284.

Added to its reverse (1284) it gives a triangular number (6105 = T₁₁₀).

4821 = 19² + 20² + ... + 27².

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 4821 - 2² = 4817 is a prime.

It is a D-number.

It is a Curzon number.

It is a plaindrome in base 13 and base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 4821.

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 4821.

It is not an unprimeable number, because it can be changed into a prime (4801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 801 + ... + 806.

It is an arithmetic number, because the mean of its divisors is an integer number (1608).

2⁴⁸²¹ is an apocalyptic number.

It is an amenable number.

4821 is a deficient number, since it is larger than the sum of its proper divisors (1611).

4821 is a wasteful number, since it uses less digits than its factorization.

4821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1610.

The product of its digits is 64, while the sum is 15.

The square root of 4821 is about 69.4334213474. The cubic root of 4821 is about 16.8932176372.

Adding to 4821 its reverse (1284), we get a triangular number (6105 = T₁₁₀).

The spelling of 4821 in words is "four thousand, eight hundred twenty-one".