21651798928896 has 200 divisors, whose sum is σ = 64845517918104. Its totient is φ = 7192629964800.

The previous prime is 21651798928889. The next prime is 21651798928931. The reversal of 21651798928896 is 69882989715612.

21651798928896 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 179 + 89 + 288 + 96 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11260371 + ... + 13042221.

Almost surely, 2^{21651798928896} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21651798928896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32422758959052).

21651798928896 is an abundant number, since it is smaller than the sum of its proper divisors (43193718989208).

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

21651798928896 is an equidigital number, since it uses as much as digits as its factorization.

21651798928896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1782174 (or 1782149 counting only the distinct ones).

The product of its digits is 1881169920, while the sum is 81.

The spelling of 21651798928896 in words is "twenty-one trillion, six hundred fifty-one billion, seven hundred ninety-eight million, nine hundred twenty-eight thousand, eight hundred ninety-six".