21663684928512 has 1408 divisors, whose sum is σ = 73702140019200. Its totient is φ = 6306398208000.

The previous prime is 21663684928499. The next prime is 21663684928531. The reversal of 21663684928512 is 21582948636612.

21663684928512 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 3 + 68 + 492 + 85 + 1 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (1408).

It is a self number, because there is not a number n which added to its sum of digits gives 21663684928512.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 89890808712 + ... + 89890808952.

It is an arithmetic number, because the mean of its divisors is an integer number (52345269900).

Almost surely, 2^{21663684928512} is an apocalyptic number.

21663684928512 is a gapful number since it is divisible by the number (22) 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 21663684928512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36851070009600).

21663684928512 is an abundant number, since it is smaller than the sum of its proper divisors (52038455090688).

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

21663684928512 is an equidigital number, since it uses as much as digits as its factorization.

21663684928512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423 (or 387 counting only the distinct ones).

The product of its digits is 59719680, while the sum is 63.

The spelling of 21663684928512 in words is "twenty-one trillion, six hundred sixty-three billion, six hundred eighty-four million, nine hundred twenty-eight thousand, five hundred twelve".