646783656960 has 352 divisors, whose sum is σ = 2371061912832. Its totient is φ = 147408814080.

The previous prime is 646783656947. The next prime is 646783656991. The reversal of 646783656960 is 69656387646.

It is a junction number, because it is equal to n+sod(n) for n = 646783656891 and 646783656900.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37946040 + ... + 37963080.

Almost surely, 2^646783656960 is an apocalyptic number.

646783656960 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 646783656960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1185530956416).

646783656960 is an abundant number, since it is smaller than the sum of its proper divisors (1724278255872).

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

646783656960 is a wasteful number, since it uses less digits than its factorization.

646783656960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17429 (or 17411 counting only the distinct ones).

The product of its (nonzero) digits is 235146240, while the sum is 66.

The spelling of 646783656960 in words is "six hundred forty-six billion, seven hundred eighty-three million, six hundred fifty-six thousand, nine hundred sixty".