20865214064640 has 768 divisors, whose sum is σ = 77763035750400. Its totient is φ = 4726200729600.

The previous prime is 20865214064627. The next prime is 20865214064647. The reversal of 20865214064640 is 4646041256802.

It is a tau number, because it is divible by the number of its divisors (768).

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 20865214064640.

It is not an unprimeable number, because it can be changed into a prime (20865214064647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 303755739 + ... + 303824421.

It is an arithmetic number, because the mean of its divisors is an integer number (101253952800).

Almost surely, 2^{20865214064640} is an apocalyptic number.

20865214064640 is a gapful number since it is divisible by the number (20) 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 20865214064640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38881517875200).

20865214064640 is an abundant number, since it is smaller than the sum of its proper divisors (56897821685760).

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

20865214064640 is a wasteful number, since it uses less digits than its factorization.

20865214064640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68784 (or 68764 counting only the distinct ones).

The product of its (nonzero) digits is 2211840, while the sum is 48.

The spelling of 20865214064640 in words is "twenty trillion, eight hundred sixty-five billion, two hundred fourteen million, sixty-four thousand, six hundred forty".