65640368640 has 960 divisors, whose sum is σ = 270645141888. Its totient is φ = 13418496000.

The previous prime is 65640368621. The next prime is 65640368687. The reversal of 65640368640 is 4686304656.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 65640368640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 418091442 + ... + 418091598.

Almost surely, 2^65640368640 is an apocalyptic number.

65640368640 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 65640368640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135322570944).

65640368640 is an abundant number, since it is smaller than the sum of its proper divisors (205004773248).

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

65640368640 is a wasteful number, since it uses less digits than its factorization.

65640368640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 286 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 48.

The spelling of 65640368640 in words is "sixty-five billion, six hundred forty million, three hundred sixty-eight thousand, six hundred forty".