72821 has 8 divisors (see below), whose sum is σ = 84864. Its totient is φ = 61200.

The previous prime is 72817. The next prime is 72823. The reversal of 72821 is 12827.

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 72821 - 2² = 72817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a nialpdrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 72793 and 72802.

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 72821.

It is not an unprimeable number, because it can be changed into a prime (72823) 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, 656 + ... + 758.

It is an arithmetic number, because the mean of its divisors is an integer number (10608).

2⁷²⁸²¹ is an apocalyptic number.

It is an amenable number.

72821 is a deficient number, since it is larger than the sum of its proper divisors (12043).

72821 is a wasteful number, since it uses less digits than its factorization.

72821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211.

The product of its digits is 224, while the sum is 20.

The square root of 72821 is about 269.8536640478. The cubic root of 72821 is about 41.7592041094.

The spelling of 72821 in words is "seventy-two thousand, eight hundred twenty-one".