21216504960 has 384 divisors, whose sum is σ = 86834966400. Its totient is φ = 4849238016.

The previous prime is 21216504949. The next prime is 21216504973. The reversal of 21216504960 is 6940561212.

21216504960 is a `hidden beast` number, since 2 + 1 + 2 + 165 + 0 + 496 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1078896 + ... + 1098384.

It is an arithmetic number, because the mean of its divisors is an integer number (226132725).

Almost surely, 2^21216504960 is an apocalyptic number.

21216504960 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 21216504960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43417483200).

21216504960 is an abundant number, since it is smaller than the sum of its proper divisors (65618461440).

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

21216504960 is an equidigital number, since it uses as much as digits as its factorization.

21216504960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19530 (or 19506 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21216504960 in words is "twenty-one billion, two hundred sixteen million, five hundred four thousand, nine hundred sixty".