645248 has 24 divisors (see below), whose sum is σ = 1303815. Its totient is φ = 318080.

The previous prime is 645233. The next prime is 645257. The reversal of 645248 is 842546.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 322624 + 322624 = 568^2 + 568^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=568.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645248.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 9053 + ... + 9123.

2⁶⁴⁵²⁴⁸ 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 645248

645248 is an abundant number, since it is smaller than the sum of its proper divisors (658567).

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

645248 is an frugal number, since it uses more digits than its factorization.

645248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 73 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 645248 is about 803.2733034279. The cubic root of 645248 is about 86.4122982037.

It can be divided in two parts, 6 and 45248, that added together give a palindrome (45254).

The spelling of 645248 in words is "six hundred forty-five thousand, two hundred forty-eight".