21780064336800 has 576 divisors, whose sum is σ = 88420744710144. Its totient is φ = 4524023500800.

The previous prime is 21780064336777. The next prime is 21780064336829. The reversal of 21780064336800 is 863346008712.

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 21780064336800.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 524256829 + ... + 524298371.

It is an arithmetic number, because the mean of its divisors is an integer number (153508237344).

Almost surely, 2^{21780064336800} is an apocalyptic number.

21780064336800 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 21780064336800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44210372355072).

21780064336800 is an abundant number, since it is smaller than the sum of its proper divisors (66640680373344).

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

21780064336800 is a wasteful number, since it uses less digits than its factorization.

21780064336800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44421 (or 44408 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 48.

The spelling of 21780064336800 in words is "twenty-one trillion, seven hundred eighty billion, sixty-four million, three hundred thirty-six thousand, eight hundred".