321816 has 64 divisors (see below), whose sum is σ = 933120. Its totient is φ = 91520.

The previous prime is 321799. The next prime is 321817. The reversal of 321816 is 618123.

It is a nude number because it is divisible by every one of its digits.

It is an alternating number because its digits alternate between odd and even.

Its product of digits (288) is a multiple of the sum of its prime factors (96).

It is a junction number, because it is equal to n+sod(n) for n = 321792 and 321801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321817) by changing a digit.

321816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6046 + ... + 6098.

It is an arithmetic number, because the mean of its divisors is an integer number (14580).

2³²¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 321816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (466560).

321816 is an abundant number, since it is smaller than the sum of its proper divisors (611304).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

321816 is a wasteful number, since it uses less digits than its factorization.

321816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96 (or 92 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 321816 is about 567.2882864999. The cubic root of 321816 is about 68.5281820565.

Adding to 321816 its reverse (618123), we get a palindrome (939939).

The spelling of 321816 in words is "three hundred twenty-one thousand, eight hundred sixteen".