646816435776 has 588 divisors, whose sum is σ = 2356577689680. Its totient is φ = 175066375680.

The previous prime is 646816435723. The next prime is 646816435777. The reversal of 646816435776 is 677534618646.

646816435776 is a `hidden beast` number, since 6 + 4 + 6 + 8 + 16 + 43 + 577 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (588).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (646816435777) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 43429291 + ... + 43444181.

Almost surely, 2^646816435776 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646816435776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1178288844840).

646816435776 is an abundant number, since it is smaller than the sum of its proper divisors (1709761253904).

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

646816435776 is a wasteful number, since it uses less digits than its factorization.

646816435776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14954 (or 14922 counting only the distinct ones).

The product of its digits is 121927680, while the sum is 63.

The spelling of 646816435776 in words is "six hundred forty-six billion, eight hundred sixteen million, four hundred thirty-five thousand, seven hundred seventy-six".