321645 has 16 divisors (see below), whose sum is σ = 528192. Its totient is φ = 167040.

The previous prime is 321631. The next prime is 321647. The reversal of 321645 is 546123.

It is a happy number.

It is not a de Polignac number, because 321645 - 2¹⁵ = 288877 is a prime.

It is a super-3 number, since 3×321645³ = 99827838706233375, which contains 333 as substring.

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 321645.

It is not an unprimeable number, because it can be changed into a prime (321647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 354 + ... + 876.

It is an arithmetic number, because the mean of its divisors is an integer number (33012).

2³²¹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

321645 is a deficient number, since it is larger than the sum of its proper divisors (206547).

321645 is a wasteful number, since it uses less digits than its factorization.

321645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572.

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

The square root of 321645 is about 567.1375494534. The cubic root of 321645 is about 68.5160422051.

Adding to 321645 its reverse (546123), we get a palindrome (867768).

The spelling of 321645 in words is "three hundred twenty-one thousand, six hundred forty-five".