21355215360 has 320 divisors, whose sum is σ = 69825888000. Its totient is φ = 5566758912.

The previous prime is 21355215331. The next prime is 21355215361. The reversal of 21355215360 is 6351255312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (320).

It is not an unprimeable number, because it can be changed into a prime (21355215361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 107312541 + ... + 107312739.

It is an arithmetic number, because the mean of its divisors is an integer number (218205900).

Almost surely, 2^21355215360 is an apocalyptic number.

21355215360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21355215360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34912944000).

21355215360 is an abundant number, since it is smaller than the sum of its proper divisors (48470672640).

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

21355215360 is a wasteful number, since it uses less digits than its factorization.

21355215360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471 (or 455 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 33.

The spelling of 21355215360 in words is "twenty-one billion, three hundred fifty-five million, two hundred fifteen thousand, three hundred sixty".