21705393696 has 96 divisors (see below), whose sum is σ = 65174151168. Its totient is φ = 6196020480.

The previous prime is 21705393691. The next prime is 21705393713. The reversal of 21705393696 is 69639350712.

It is a happy number.

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

It is a super-2 number, since 2×21705393696² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21705393691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 773121 + ... + 800703.

It is an arithmetic number, because the mean of its divisors is an integer number (678897408).

Almost surely, 2^21705393696 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 21705393696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32587075584).

21705393696 is an abundant number, since it is smaller than the sum of its proper divisors (43468757472).

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

21705393696 is a wasteful number, since it uses less digits than its factorization.

21705393696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28774 (or 28766 counting only the distinct ones).

The product of its (nonzero) digits is 1837080, while the sum is 51.

The spelling of 21705393696 in words is "twenty-one billion, seven hundred five million, three hundred ninety-three thousand, six hundred ninety-six".