645213 has 8 divisors (see below), whose sum is σ = 864000. Its totient is φ = 428288.

The previous prime is 645187. The next prime is 645233. The reversal of 645213 is 312546.

It is a happy number.

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 645213 - 2⁶ = 645149 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 645213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1108 + ... + 1586.

It is an arithmetic number, because the mean of its divisors is an integer number (108000).

2⁶⁴⁵²¹³ is an apocalyptic number.

It is an amenable number.

645213 is a deficient number, since it is larger than the sum of its proper divisors (218787).

645213 is a wasteful number, since it uses less digits than its factorization.

645213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 931.

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

The square root of 645213 is about 803.2515172721. The cubic root of 645213 is about 86.4107357630.

Adding to 645213 its reverse (312546), we get a palindrome (957759).

It can be divided in two parts, 645 and 213, that added together give a palindrome (858).

The spelling of 645213 in words is "six hundred forty-five thousand, two hundred thirteen".