64865888640 has 320 divisors, whose sum is σ = 264741824160. Its totient is φ = 14826405888.

The previous prime is 64865888617. The next prime is 64865888719. The reversal of 64865888640 is 4688856846.

64865888640 is a `hidden beast` number, since 6 + 4 + 8 + 6 + 588 + 8 + 6 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 273504 + ... + 452256.

Almost surely, 2^64865888640 is an apocalyptic number.

64865888640 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 64865888640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132370912080).

64865888640 is an abundant number, since it is smaller than the sum of its proper divisors (199875935520).

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

64865888640 is a wasteful number, since it uses less digits than its factorization.

64865888640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178791 (or 178770 counting only the distinct ones).

The product of its (nonzero) digits is 70778880, while the sum is 63.

The spelling of 64865888640 in words is "sixty-four billion, eight hundred sixty-five million, eight hundred eighty-eight thousand, six hundred forty".