21055438813420 has 192 divisors, whose sum is σ = 52283767818240. Its totient is φ = 7099209469440.

The previous prime is 21055438813351. The next prime is 21055438813441. The reversal of 21055438813420 is 2431883455012.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 23328792 + ... + 24214528.

It is an arithmetic number, because the mean of its divisors is an integer number (272311290720).

Almost surely, 2^{21055438813420} is an apocalyptic number.

21055438813420 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 21055438813420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26141883909120).

21055438813420 is an abundant number, since it is smaller than the sum of its proper divisors (31228329004820).

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

21055438813420 is a wasteful number, since it uses less digits than its factorization.

21055438813420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 885845 (or 885821 counting only the distinct ones).

The product of its (nonzero) digits is 921600, while the sum is 46.

The spelling of 21055438813420 in words is "twenty-one trillion, fifty-five billion, four hundred thirty-eight million, eight hundred thirteen thousand, four hundred twenty".