646044840 has 384 divisors, whose sum is σ = 2569881600. Its totient is φ = 137479680.

The previous prime is 646044823. The next prime is 646044851. The reversal of 646044840 is 48440646.

646044840 is a `hidden beast` number, since 6 + 4 + 604 + 4 + 8 + 40 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 646044795 and 646044804.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4931575 + ... + 4931705.

It is an arithmetic number, because the mean of its divisors is an integer number (6692400).

Almost surely, 2^646044840 is an apocalyptic number.

646044840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646044840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1284940800).

646044840 is an abundant number, since it is smaller than the sum of its proper divisors (1923836760).

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

646044840 is a wasteful number, since it uses less digits than its factorization.

646044840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 270 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 36.

The square root of 646044840 is about 25417.4121420730. The cubic root of 646044840 is about 864.4785479098.

The spelling of 646044840 in words is "six hundred forty-six million, forty-four thousand, eight hundred forty".