996821 has 4 divisors (see below), whose sum is σ = 1139232. Its totient is φ = 854412.

The previous prime is 996811. The next prime is 996841. The reversal of 996821 is 128699.

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 a de Polignac number, because none of the positive numbers 2^k-996821 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (996811) 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 3 ways as a sum of consecutive naturals, for example, 71195 + ... + 71208.

It is an arithmetic number, because the mean of its divisors is an integer number (284808).

2⁹⁹⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

996821 is a deficient number, since it is larger than the sum of its proper divisors (142411).

996821 is a wasteful number, since it uses less digits than its factorization.

996821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142410.

The product of its digits is 7776, while the sum is 35.

The square root of 996821 is about 998.4092347329. The cubic root of 996821 is about 99.8939208453.

The spelling of 996821 in words is "nine hundred ninety-six thousand, eight hundred twenty-one".