646909943040 has 576 divisors, whose sum is σ = 2367662330880. Its totient is φ = 167160913920.

The previous prime is 646909942979. The next prime is 646909943047. The reversal of 646909943040 is 40349909646.

646909943040 is a `hidden beast` number, since 64 + 69 + 0 + 99 + 430 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646909943047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 194674819 + ... + 194678141.

It is an arithmetic number, because the mean of its divisors is an integer number (4110524880).

Almost surely, 2^646909943040 is an apocalyptic number.

646909943040 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 646909943040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1183831165440).

646909943040 is an abundant number, since it is smaller than the sum of its proper divisors (1720752387840).

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

646909943040 is a wasteful number, since it uses less digits than its factorization.

646909943040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3527 (or 3507 counting only the distinct ones).

The product of its (nonzero) digits is 5038848, while the sum is 54.

The spelling of 646909943040 in words is "six hundred forty-six billion, nine hundred nine million, nine hundred forty-three thousand, forty".