21816042336 has 384 divisors, whose sum is σ = 74449912320. Its totient is φ = 6218311680.

The previous prime is 21816042263. The next prime is 21816042349. The reversal of 21816042336 is 63324061812.

21816042336 is a `hidden beast` number, since 2 + 18 + 1 + 604 + 2 + 3 + 36 = 666.

It is a super-2 number, since 2×21816042336² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21816042336.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13086175 + ... + 13087841.

It is an arithmetic number, because the mean of its divisors is an integer number (193879980).

Almost surely, 2^21816042336 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 21816042336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37224956160).

21816042336 is an abundant number, since it is smaller than the sum of its proper divisors (52633869984).

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

21816042336 is a wasteful number, since it uses less digits than its factorization.

21816042336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1726 (or 1700 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The spelling of 21816042336 in words is "twenty-one billion, eight hundred sixteen million, forty-two thousand, three hundred thirty-six".