21678299294976 has 144 divisors (see below), whose sum is σ = 65597395568320. Its totient is φ = 7058050836480.

The previous prime is 21678299294959. The next prime is 21678299294987. The reversal of 21678299294976 is 67949299287612.

21678299294976 is a `hidden beast` number, since 2 + 16 + 7 + 8 + 2 + 99 + 29 + 497 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 21678299294895 and 21678299294904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36171715 + ... + 36766146.

Almost surely, 2^{21678299294976} is an apocalyptic number.

It is an amenable number.

21678299294976 is an abundant number, since it is smaller than the sum of its proper divisors (43919096273344).

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

21678299294976 is an equidigital number, since it uses as much as digits as its factorization.

21678299294976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72937929 (or 72937909 counting only the distinct ones).

The product of its digits is 2962842624, while the sum is 81.

The spelling of 21678299294976 in words is "twenty-one trillion, six hundred seventy-eight billion, two hundred ninety-nine million, two hundred ninety-four thousand, nine hundred seventy-six".