645344 has 48 divisors (see below), whose sum is σ = 1507968. Its totient is φ = 266112.

The previous prime is 645329. The next prime is 645347. The reversal of 645344 is 443546.

645344 is nontrivially palindromic in base 6.

It is an Ulam 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 645344.

It is not an unprimeable number, because it can be changed into a prime (645347) by changing a digit.

645344 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, 9599 + ... + 9665.

It is an arithmetic number, because the mean of its divisors is an integer number (31416).

2⁶⁴⁵³⁴⁴ 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 645344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (753984).

645344 is an abundant number, since it is smaller than the sum of its proper divisors (862624).

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

645344 is a wasteful number, since it uses less digits than its factorization.

645344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 119 counting only the distinct ones).

The product of its digits is 5760, while the sum is 26.

The square root of 645344 is about 803.3330567081. Note that the first 3 decimals coincide. The cubic root of 645344 is about 86.4165834652.

It can be divided in two parts, 645 and 344, that added together give a palindrome (989).

The spelling of 645344 in words is "six hundred forty-five thousand, three hundred forty-four".