648640 has 28 divisors (see below), whose sum is σ = 1545336. Its totient is φ = 259328.

The previous prime is 648631. The next prime is 648649. The reversal of 648640 is 46846.

It is an interprime number because it is at equal distance from previous prime (648631) and next prime (648649).

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 648599 and 648608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648649) 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, 694 + ... + 1333.

2⁶⁴⁸⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

648640 is an abundant number, since it is smaller than the sum of its proper divisors (896696).

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

648640 is a wasteful number, since it uses less digits than its factorization.

648640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2044 (or 2034 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 648640 is about 805.3818969905. The cubic root of 648640 is about 86.5634537249.

The spelling of 648640 in words is "six hundred forty-eight thousand, six hundred forty".