21653064016544 has 192 divisors, whose sum is σ = 45749787697152. Its totient is φ = 10052550144000.

The previous prime is 21653064016543. The next prime is 21653064016547. The reversal of 21653064016544 is 44561046035612.

It is not an unprimeable number, because it can be changed into a prime (21653064016543) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7928619659 + ... + 7928622389.

It is an arithmetic number, because the mean of its divisors is an integer number (238280144256).

Almost surely, 2^{21653064016544} 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 21653064016544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22874893848576).

21653064016544 is an abundant number, since it is smaller than the sum of its proper divisors (24096723680608).

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

21653064016544 is a wasteful number, since it uses less digits than its factorization.

21653064016544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3539 (or 3531 counting only the distinct ones).

The product of its (nonzero) digits is 2073600, while the sum is 47.

The spelling of 21653064016544 in words is "twenty-one trillion, six hundred fifty-three billion, sixty-four million, sixteen thousand, five hundred forty-four".