648840 has 32 divisors (see below), whose sum is σ = 1946880. Its totient is φ = 172992.

The previous prime is 648803. The next prime is 648841. The reversal of 648840 is 48846.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 648798 and 648807.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 648840.

It is not an unprimeable number, because it can be changed into a prime (648841) by changing a digit.

648840 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, 2584 + ... + 2823.

It is an arithmetic number, because the mean of its divisors is an integer number (60840).

2⁶⁴⁸⁸⁴⁰ is an apocalyptic number.

648840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

648840 is an abundant number, since it is smaller than the sum of its proper divisors (1298040).

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

648840 is a wasteful number, since it uses less digits than its factorization.

648840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5421 (or 5417 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 648840 is about 805.5060521188. The cubic root of 648840 is about 86.5723497287.

The spelling of 648840 in words is "six hundred forty-eight thousand, eight hundred forty".