21717540544 has 112 divisors (see below), whose sum is σ = 50943963136. Its totient is φ = 8989056000.

The previous prime is 21717540529. The next prime is 21717540553. The reversal of 21717540544 is 44504571712.

It is a tau number, because it is divible by the number of its divisors (112).

It is a junction number, because it is equal to n+sod(n) for n = 21717540497 and 21717540506.

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, 8512069 + ... + 8514619.

Almost surely, 2^21717540544 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 21717540544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25471981568).

21717540544 is an abundant number, since it is smaller than the sum of its proper divisors (29226422592).

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

21717540544 is a wasteful number, since it uses less digits than its factorization.

21717540544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3214 (or 3204 counting only the distinct ones).

The product of its (nonzero) digits is 156800, while the sum is 40.

The spelling of 21717540544 in words is "twenty-one billion, seven hundred seventeen million, five hundred forty thousand, five hundred forty-four".