21778938206560 has 48 divisors (see below), whose sum is σ = 53112507380352. Its totient is φ = 8430556723200.

The previous prime is 21778938206549. The next prime is 21778938206563. The reversal of 21778938206560 is 6560283987712.

It is a junction number, because it is equal to n+sod(n) for n = 21778938206492 and 21778938206501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21778938206563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2195452521 + ... + 2195462440.

It is an arithmetic number, because the mean of its divisors is an integer number (1106510570424).

Almost surely, 2^{21778938206560} is an apocalyptic number.

21778938206560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21778938206560 is an abundant number, since it is smaller than the sum of its proper divisors (31333569173792).

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

21778938206560 is a wasteful number, since it uses less digits than its factorization.

21778938206560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4390915007 (or 4390914999 counting only the distinct ones).

The product of its (nonzero) digits is 60963840, while the sum is 64.

The spelling of 21778938206560 in words is "twenty-one trillion, seven hundred seventy-eight billion, nine hundred thirty-eight million, two hundred six thousand, five hundred sixty".