21612648657600 has 2016 divisors, whose sum is σ = 107673233472000. Its totient is φ = 4145424998400.

The previous prime is 21612648657581. The next prime is 21612648657631. The reversal of 21612648657600 is 675684621612.

21612648657600 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 2 + 64 + 8 + 6 + 576 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2016).

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

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 302666701 + ... + 302738099.

It is an arithmetic number, because the mean of its divisors is an integer number (53409342000).

Almost surely, 2^{21612648657600} is an apocalyptic number.

21612648657600 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 21612648657600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53836616736000).

21612648657600 is an abundant number, since it is smaller than the sum of its proper divisors (86060584814400).

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

21612648657600 is a wasteful number, since it uses less digits than its factorization.

21612648657600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71468 (or 71440 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 21612648657600 in words is "twenty-one trillion, six hundred twelve billion, six hundred forty-eight million, six hundred fifty-seven thousand, six hundred".