821633 has 4 divisors (see below), whose sum is σ = 823728. Its totient is φ = 819540.

The previous prime is 821603. The next prime is 821641. The reversal of 821633 is 336128.

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 not a de Polignac number, because 821633 - 2⁸ = 821377 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 821599 and 821608.

It is not an unprimeable number, because it can be changed into a prime (821603) 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 3 ways as a sum of consecutive naturals, for example, 263 + ... + 1308.

It is an arithmetic number, because the mean of its divisors is an integer number (205932).

2⁸²¹⁶³³ is an apocalyptic number.

It is an amenable number.

821633 is a deficient number, since it is larger than the sum of its proper divisors (2095).

821633 is a wasteful number, since it uses less digits than its factorization.

821633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2094.

The product of its digits is 864, while the sum is 23.

The square root of 821633 is about 906.4397387582. The cubic root of 821633 is about 93.6611080373.

The spelling of 821633 in words is "eight hundred twenty-one thousand, six hundred thirty-three".