823521 has 8 divisors (see below), whose sum is σ = 1103104. Its totient is φ = 546480.

The previous prime is 823519. The next prime is 823541. The reversal of 823521 is 125328.

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

It is not a de Polignac number, because 823521 - 2¹ = 823519 is a prime.

It is a Duffinian number.

823521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (823541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 336 + ... + 1326.

It is an arithmetic number, because the mean of its divisors is an integer number (137888).

2⁸²³⁵²¹ is an apocalyptic number.

It is an amenable number.

823521 is a deficient number, since it is larger than the sum of its proper divisors (279583).

823521 is a wasteful number, since it uses less digits than its factorization.

823521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1271.

The product of its digits is 480, while the sum is 21.

The square root of 823521 is about 907.4805783046. The cubic root of 823521 is about 93.7327932865.

Adding to 823521 its reverse (125328), we get a palindrome (948849).

It can be divided in two parts, 8235 and 21, that added together give a triangular number (8256 = T₁₂₈).

The spelling of 823521 in words is "eight hundred twenty-three thousand, five hundred twenty-one".