21017053536 has 96 divisors (see below), whose sum is σ = 57483820800. Its totient is φ = 6715322880.

The previous prime is 21017053529. The next prime is 21017053543. The reversal of 21017053536 is 63535071012.

It is an interprime number because it is at equal distance from previous prime (21017053529) and next prime (21017053543).

It is a tau number, because it is divible by the number of its divisors (96).

It is a junction number, because it is equal to n+sod(n) for n = 21017053497 and 21017053506.

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, 359821 + ... + 414131.

It is an arithmetic number, because the mean of its divisors is an integer number (598789800).

Almost surely, 2^21017053536 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 21017053536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28741910400).

21017053536 is an abundant number, since it is smaller than the sum of its proper divisors (36466767264).

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

21017053536 is a wasteful number, since it uses less digits than its factorization.

21017053536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54492 (or 54484 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 33.

The spelling of 21017053536 in words is "twenty-one billion, seventeen million, fifty-three thousand, five hundred thirty-six".