826821 has 16 divisors (see below), whose sum is σ = 1240320. Its totient is φ = 544320.

The previous prime is 826811. The next prime is 826831. The reversal of 826821 is 128628.

It is an interprime number because it is at equal distance from previous prime (826811) and next prime (826831).

It is not a de Polignac number, because 826821 - 2¹¹ = 824773 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (826811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2916 + ... + 3186.

It is an arithmetic number, because the mean of its divisors is an integer number (77520).

2⁸²⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

826821 is a deficient number, since it is larger than the sum of its proper divisors (413499).

826821 is a wasteful number, since it uses less digits than its factorization.

826821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 393 (or 387 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 826821 is about 909.2969811893. The cubic root of 826821 is about 93.8578279326.

It can be divided in two parts, 82 and 6821, that added together give a triangular number (6903 = T₁₁₇).

The spelling of 826821 in words is "eight hundred twenty-six thousand, eight hundred twenty-one".