21129855533280 has 288 divisors, whose sum is σ = 79546178537280. Its totient is φ = 5074336604160.

The previous prime is 21129855533263. The next prime is 21129855533291. The reversal of 21129855533280 is 8233555892112.

21129855533280 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 9 + 8 + 5 + 553 + 3 + 2 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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 47 ways as a sum of consecutive naturals, for example, 12997500 + ... + 14532539.

It is an arithmetic number, because the mean of its divisors is an integer number (276202008810).

Almost surely, 2^{21129855533280} is an apocalyptic number.

21129855533280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21129855533280 is an abundant number, since it is smaller than the sum of its proper divisors (58416323004000).

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

21129855533280 is a wasteful number, since it uses less digits than its factorization.

21129855533280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27530114 (or 27530103 counting only the distinct ones).

The product of its (nonzero) digits is 5184000, while the sum is 54.

The spelling of 21129855533280 in words is "twenty-one trillion, one hundred twenty-nine billion, eight hundred fifty-five million, five hundred thirty-three thousand, two hundred eighty".