321216 has 56 divisors (see below), whose sum is σ = 975360. Its totient is φ = 91392.

The previous prime is 321203. The next prime is 321221. The reversal of 321216 is 612123.

It is a tau number, because it is divible by the number of its divisors (56).

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.

It is a junction number, because it is equal to n+sod(n) for n = 321195 and 321204.

It is an unprimeable number.

321216 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 7 ways as a sum of consecutive naturals, for example, 1225 + ... + 1463.

2³²¹²¹⁶ 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 321216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (487680).

321216 is an abundant number, since it is smaller than the sum of its proper divisors (654144).

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

321216 is a wasteful number, since it uses less digits than its factorization.

321216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 251 counting only the distinct ones).

The product of its digits is 72, while the sum is 15.

The square root of 321216 is about 566.7592081299. The cubic root of 321216 is about 68.4855671370.

Subtracting from 321216 its sum of digits (15), we obtain a triangular number (321201 = T₈₀₁).

Adding to 321216 its reverse (612123), we get a palindrome (933339).

The spelling of 321216 in words is "three hundred twenty-one thousand, two hundred sixteen".