21104659779840 has 3456 divisors, whose sum is σ = 100793243980800. Its totient is φ = 4066671329280.

The previous prime is 21104659779809. The next prime is 21104659779851. The reversal of 21104659779840 is 4897795640112.

21104659779840 is a `hidden beast` number, since 2 + 1 + 1 + 0 + 465 + 97 + 7 + 9 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (3456).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 32924585920 + ... + 32924586560.

It is an arithmetic number, because the mean of its divisors is an integer number (29164711800).

Almost surely, 2^{21104659779840} is an apocalyptic number.

21104659779840 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 21104659779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50396621990400).

21104659779840 is an abundant number, since it is smaller than the sum of its proper divisors (79688584200960).

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

21104659779840 is a wasteful number, since it uses less digits than its factorization.

21104659779840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758 (or 719 counting only the distinct ones).

The product of its (nonzero) digits is 30481920, while the sum is 63.

The spelling of 21104659779840 in words is "twenty-one trillion, one hundred four billion, six hundred fifty-nine million, seven hundred seventy-nine thousand, eight hundred forty".