21593793816 has 384 divisors, whose sum is σ = 72405964800. Its totient is φ = 5677102080.

The previous prime is 21593793803. The next prime is 21593793857. The reversal of 21593793816 is 61839739512.

21593793816 is a `hidden beast` number, since 2 + 1 + 593 + 7 + 9 + 38 + 16 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 79681761 + ... + 79682031.

It is an arithmetic number, because the mean of its divisors is an integer number (188557200).

Almost surely, 2^21593793816 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 21593793816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36202982400).

21593793816 is an abundant number, since it is smaller than the sum of its proper divisors (50812170984).

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

21593793816 is a wasteful number, since it uses less digits than its factorization.

21593793816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519 (or 512 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 54.

It can be divided in two parts, 21593793 and 816, that added together give a square (21594609 = 4647²).

The spelling of 21593793816 in words is "twenty-one billion, five hundred ninety-three million, seven hundred ninety-three thousand, eight hundred sixteen".