21781206426960 has 480 divisors, whose sum is σ = 80145887477760. Its totient is φ = 5277339648000.

The previous prime is 21781206426953. The next prime is 21781206426979. The reversal of 21781206426960 is 6962460218712.

21781206426960 is a `hidden beast` number, since 2 + 1 + 7 + 8 + 1 + 206 + 426 + 9 + 6 + 0 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21781206426897 and 21781206426906.

It is a congruent number.

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, 155120785 + ... + 155261135.

It is an arithmetic number, because the mean of its divisors is an integer number (166970598912).

Almost surely, 2^{21781206426960} is an apocalyptic number.

21781206426960 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 21781206426960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40072943738880).

21781206426960 is an abundant number, since it is smaller than the sum of its proper divisors (58364681050800).

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

21781206426960 is a wasteful number, since it uses less digits than its factorization.

21781206426960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140827 (or 140818 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The spelling of 21781206426960 in words is "twenty-one trillion, seven hundred eighty-one billion, two hundred six million, four hundred twenty-six thousand, nine hundred sixty".