821836 has 12 divisors (see below), whose sum is σ = 1500912. Its totient is φ = 393008.

The previous prime is 821833. The next prime is 821851. The reversal of 821836 is 638128.

821836 = T₈₅ + T₈₆ + ... + T₁₇₆.

It is a super-3 number, since 3×821836³ = 1665239633379375168, which contains 333 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4375 + ... + 4558.

It is an arithmetic number, because the mean of its divisors is an integer number (125076).

2⁸²¹⁸³⁶ is an apocalyptic number.

It is an amenable number.

821836 is a deficient number, since it is larger than the sum of its proper divisors (679076).

821836 is a wasteful number, since it uses less digits than its factorization.

821836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8960 (or 8958 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 821836 is about 906.5517083984. The cubic root of 821836 is about 93.6688209859.

The spelling of 821836 in words is "eight hundred twenty-one thousand, eight hundred thirty-six".