645648 has 20 divisors (see below), whose sum is σ = 1668048. Its totient is φ = 215200.

The previous prime is 645647. The next prime is 645649. The reversal of 645648 is 846546.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (645647) and next prime (645649).

It is a super-2 number, since 2×645648² = 833722679808, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645648.

It is not an unprimeable number, because it can be changed into a prime (645641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6678 + ... + 6773.

2⁶⁴⁵⁶⁴⁸ is an apocalyptic number.

It is an amenable number.

645648 is an abundant number, since it is smaller than the sum of its proper divisors (1022400).

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

645648 is a wasteful number, since it uses less digits than its factorization.

645648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13462 (or 13456 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 645648 is about 803.5222461139. The cubic root of 645648 is about 86.4301506569.

It can be divided in two parts, 6 and 45648, that added together give a palindrome (45654).

The spelling of 645648 in words is "six hundred forty-five thousand, six hundred forty-eight".