321564 has 24 divisors (see below), whose sum is σ = 759808. Its totient is φ = 105840.

The previous prime is 321553. The next prime is 321569. The reversal of 321564 is 465123.

It is a happy number.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 321564.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 321564.

It is not an unprimeable number, because it can be changed into a prime (321569) by changing a digit.

321564 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, 1419 + ... + 1629.

2³²¹⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

321564 is an abundant number, since it is smaller than the sum of its proper divisors (438244).

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

321564 is a wasteful number, since it uses less digits than its factorization.

321564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 343 counting only the distinct ones).

The product of its digits is 720, while the sum is 21.

The square root of 321564 is about 567.0661337093. The cubic root of 321564 is about 68.5102902473.

Adding to 321564 its reverse (465123), we get a palindrome (786687).

It can be divided in two parts, 32 and 1564, that added together give a triangular number (1596 = T₅₆).

The spelling of 321564 in words is "three hundred twenty-one thousand, five hundred sixty-four".