21388028356800 has 2352 divisors, whose sum is σ = 94930732972800. Its totient is φ = 4637083852800.

The previous prime is 21388028356759. The next prime is 21388028356801. The reversal of 21388028356800 is 865382088312.

21388028356800 is a `hidden beast` number, since 2 + 138 + 80 + 2 + 8 + 356 + 80 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21388028356801) by changing a digit.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 13969972035 + ... + 13969973565.

Almost surely, 2^{21388028356800} is an apocalyptic number.

21388028356800 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 21388028356800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47465366486400).

21388028356800 is an abundant number, since it is smaller than the sum of its proper divisors (73542704616000).

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

21388028356800 is a wasteful number, since it uses less digits than its factorization.

21388028356800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1666 (or 1636 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

The spelling of 21388028356800 in words is "twenty-one trillion, three hundred eighty-eight billion, twenty-eight million, three hundred fifty-six thousand, eight hundred".