865353728816640 has 2560 divisors, whose sum is σ = 3673824197345280. Its totient is φ = 188919624499200.

The previous prime is 865353728816587. The next prime is 865353728816653. The reversal of 865353728816640 is 46618827353568.

865353728816640 is a `hidden beast` number, since 8 + 6 + 5 + 3 + 537 + 2 + 8 + 81 + 6 + 6 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2560).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 401929273804 + ... + 401929275956.

It is an arithmetic number, because the mean of its divisors is an integer number (1435087577088).

Almost surely, 2^{865353728816640} is an apocalyptic number.

865353728816640 is a gapful number since it is divisible by the number (80) 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 865353728816640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1836912098672640).

865353728816640 is an abundant number, since it is smaller than the sum of its proper divisors (2808470468528640).

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

865353728816640 is a wasteful number, since it uses less digits than its factorization.

865353728816640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2561 (or 2539 counting only the distinct ones).

The product of its (nonzero) digits is 1393459200, while the sum is 72.

The spelling of 865353728816640 in words is "eight hundred sixty-five trillion, three hundred fifty-three billion, seven hundred twenty-eight million, eight hundred sixteen thousand, six hundred forty".