21129218530560 has 2160 divisors, whose sum is σ = 93521192965200. Its totient is φ = 4525955481600.

The previous prime is 21129218530457. The next prime is 21129218530579. The reversal of 21129218530560 is 6503581292112.

21129218530560 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 9 + 2 + 1 + 85 + 3 + 0 + 560 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 3222915381504 + 17906303149056 = 1795248^2 + 4231584^2 .

It is a tau number, because it is divible by the number of its divisors (2160).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 30141538210 + ... + 30141538910.

It is an arithmetic number, because the mean of its divisors is an integer number (43296848595).

Almost surely, 2^{21129218530560} is an apocalyptic number.

21129218530560 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 21129218530560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46760596482600).

21129218530560 is an abundant number, since it is smaller than the sum of its proper divisors (72391974434640).

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

21129218530560 is a wasteful number, since it uses less digits than its factorization.

21129218530560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1114 (or 1084 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 21129218530560 in words is "twenty-one trillion, one hundred twenty-nine billion, two hundred eighteen million, five hundred thirty thousand, five hundred sixty".