21656455558848 has 672 divisors, whose sum is σ = 71939687016960. Its totient is φ = 6335551641600.

The previous prime is 21656455558841. The next prime is 21656455558849. The reversal of 21656455558848 is 84885555465612.

21656455558848 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 6 + 455 + 55 + 88 + 48 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (21656455558841) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9188142886 + ... + 9188145242.

It is an arithmetic number, because the mean of its divisors is an integer number (107053105680).

Almost surely, 2^{21656455558848} 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 21656455558848, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35969843508480).

21656455558848 is an abundant number, since it is smaller than the sum of its proper divisors (50283231458112).

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

21656455558848 is a wasteful number, since it uses less digits than its factorization.

21656455558848 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2954 (or 2907 counting only the distinct ones).

The product of its digits is 1843200000, while the sum is 72.

The spelling of 21656455558848 in words is "twenty-one trillion, six hundred fifty-six billion, four hundred fifty-five million, five hundred fifty-eight thousand, eight hundred forty-eight".