636494544768 has 128 divisors (see below), whose sum is σ = 1737444597120. Its totient is φ = 206304454656.

The previous prime is 636494544767. The next prime is 636494544823. The reversal of 636494544768 is 867445494636.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 636494544699 and 636494544708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636494544767) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24808555 + ... + 24834197.

It is an arithmetic number, because the mean of its divisors is an integer number (13573785915).

Almost surely, 2^636494544768 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 636494544768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (868722298560).

636494544768 is an abundant number, since it is smaller than the sum of its proper divisors (1100950052352).

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

636494544768 is a wasteful number, since it uses less digits than its factorization.

636494544768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27444 (or 27432 counting only the distinct ones).

The product of its digits is 418037760, while the sum is 66.

The spelling of 636494544768 in words is "six hundred thirty-six billion, four hundred ninety-four million, five hundred forty-four thousand, seven hundred sixty-eight".