76821 has 8 divisors (see below), whose sum is σ = 106080. Its totient is φ = 49392.

The previous prime is 76819. The next prime is 76829. The reversal of 76821 is 12867.

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

It is not a de Polignac number, because 76821 - 2¹ = 76819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 76791 and 76800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (76829) 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 7 ways as a sum of consecutive naturals, for example, 355 + ... + 528.

It is an arithmetic number, because the mean of its divisors is an integer number (13260).

2⁷⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

76821 is a deficient number, since it is larger than the sum of its proper divisors (29259).

76821 is a wasteful number, since it uses less digits than its factorization.

76821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915.

The product of its digits is 672, while the sum is 24.

The square root of 76821 is about 277.1660152327. The cubic root of 76821 is about 42.5102166903.

The spelling of 76821 in words is "seventy-six thousand, eight hundred twenty-one".