64641838068 has 18 divisors (see below), whose sum is σ = 163400201874. Its totient is φ = 21547279344.

The previous prime is 64641837971. The next prime is 64641838069. The reversal of 64641838068 is 86083814646.

It can be written as a sum of positive squares in only one way, i.e., 60938872164 + 3702965904 = 246858^2 + 60852^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64641838069) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 897803271 + ... + 897803342.

It is an arithmetic number, because the mean of its divisors is an integer number (9077788993).

Almost surely, 2^64641838068 is an apocalyptic number.

It is an amenable number.

64641838068 is an abundant number, since it is smaller than the sum of its proper divisors (98758363806).

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

64641838068 is a wasteful number, since it uses less digits than its factorization.

64641838068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795606623 (or 1795606618 counting only the distinct ones).

The product of its (nonzero) digits is 5308416, while the sum is 54.

It can be divided in two parts, 646418 and 38068, that added together give a palindrome (684486).

The spelling of 64641838068 in words is "sixty-four billion, six hundred forty-one million, eight hundred thirty-eight thousand, sixty-eight".