21231520384 has 64 divisors (see below), whose sum is σ = 43338731040. Its totient is φ = 10355014656.

The previous prime is 21231520381. The next prime is 21231520391. The reversal of 21231520384 is 48302513212.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (21231520381) 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 7 ways as a sum of consecutive naturals, for example, 4990002 + ... + 4994254.

Almost surely, 2^21231520384 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 21231520384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21669365520).

21231520384 is an abundant number, since it is smaller than the sum of its proper divisors (22107210656).

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

21231520384 is an equidigital number, since it uses as much as digits as its factorization.

21231520384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5217 (or 5205 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The spelling of 21231520384 in words is "twenty-one billion, two hundred thirty-one million, five hundred twenty thousand, three hundred eighty-four".