646682136534 has 128 divisors (see below), whose sum is σ = 1687438725120. Its totient is φ = 179699845248.

The previous prime is 646682136437. The next prime is 646682136547. The reversal of 646682136534 is 435631286646.

646682136534 is a `hidden beast` number, since 6 + 46 + 68 + 2 + 1 + 3 + 6 + 534 = 666.

646682136534 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

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, 40929124 + ... + 40944920.

It is an arithmetic number, because the mean of its divisors is an integer number (13183115040).

Almost surely, 2^646682136534 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646682136534, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (843719362560).

646682136534 is an abundant number, since it is smaller than the sum of its proper divisors (1040756588586).

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

646682136534 is a wasteful number, since it uses less digits than its factorization.

646682136534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18779 (or 18773 counting only the distinct ones).

The product of its digits is 14929920, while the sum is 54.

The spelling of 646682136534 in words is "six hundred forty-six billion, six hundred eighty-two million, one hundred thirty-six thousand, five hundred thirty-four".