21388758531840 has 1728 divisors, whose sum is σ = 91684675031040. Its totient is φ = 4702924800000.

The previous prime is 21388758531827. The next prime is 21388758531851. The reversal of 21388758531840 is 4813585788312.

21388758531840 is a `hidden beast` number, since 2 + 1 + 3 + 8 + 8 + 7 + 58 + 531 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 9501890715 + ... + 9501892965.

Almost surely, 2^{21388758531840} is an apocalyptic number.

21388758531840 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 21388758531840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45842337515520).

21388758531840 is an abundant number, since it is smaller than the sum of its proper divisors (70295916499200).

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

21388758531840 is a wasteful number, since it uses less digits than its factorization.

21388758531840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2507 (or 2480 counting only the distinct ones).

The product of its (nonzero) digits is 51609600, while the sum is 63.

The spelling of 21388758531840 in words is "twenty-one trillion, three hundred eighty-eight billion, seven hundred fifty-eight million, five hundred thirty-one thousand, eight hundred forty".