645321 has 8 divisors (see below), whose sum is σ = 864864. Its totient is φ = 428000.

The previous prime is 645313. The next prime is 645329. The reversal of 645321 is 123546.

It is a happy number.

645321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (645313) and next prime (645329).

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

It is a cyclic number.

It is not a de Polignac number, because 645321 - 2³ = 645313 is a prime.

It is a Curzon number.

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 645321.

It is not an unprimeable number, because it can be changed into a prime (645329) 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, 325 + ... + 1181.

It is an arithmetic number, because the mean of its divisors is an integer number (108108).

2⁶⁴⁵³²¹ is an apocalyptic number.

It is an amenable number.

645321 is a deficient number, since it is larger than the sum of its proper divisors (219543).

645321 is a wasteful number, since it uses less digits than its factorization.

645321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111.

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

The square root of 645321 is about 803.3187412229. The cubic root of 645321 is about 86.4155568266.

Adding to 645321 its reverse (123546), we get a palindrome (768867).

The spelling of 645321 in words is "six hundred forty-five thousand, three hundred twenty-one".