21278429044560 has 240 divisors, whose sum is σ = 73412462082960. Its totient is φ = 5519306096640.

The previous prime is 21278429044507. The next prime is 21278429044577. The reversal of 21278429044560 is 6544092487212.

21278429044560 is a `hidden beast` number, since 2 + 1 + 2 + 78 + 4 + 2 + 9 + 0 + 4 + 4 + 560 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 44433267264 + 21233995777296 = 210792^2 + 4608036^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a junction number, because it is equal to n+sod(n) for n = 21278429044497 and 21278429044506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 94219456 + ... + 94445024.

It is an arithmetic number, because the mean of its divisors is an integer number (305885258679).

Almost surely, 2^{21278429044560} is an apocalyptic number.

21278429044560 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 21278429044560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36706231041480).

21278429044560 is an abundant number, since it is smaller than the sum of its proper divisors (52134033038400).

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

21278429044560 is a wasteful number, since it uses less digits than its factorization.

21278429044560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229166 (or 229157 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 21278429044560 in words is "twenty-one trillion, two hundred seventy-eight billion, four hundred twenty-nine million, forty-four thousand, five hundred sixty".