21456420480 has 640 divisors, whose sum is σ = 84454824960. Its totient is φ = 5148057600.

The previous prime is 21456420463. The next prime is 21456420523. The reversal of 21456420480 is 8402465412.

21456420480 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 642 + 0 + 4 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 108915742 + ... + 108915938.

It is an arithmetic number, because the mean of its divisors is an integer number (131960664).

Almost surely, 2^21456420480 is an apocalyptic number.

21456420480 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 21456420480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42227412480).

21456420480 is an abundant number, since it is smaller than the sum of its proper divisors (62998404480).

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

21456420480 is a wasteful number, since it uses less digits than its factorization.

21456420480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430 (or 409 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 36.

Adding to 21456420480 its reverse (8402465412), we get a palindrome (29858885892).

The spelling of 21456420480 in words is "twenty-one billion, four hundred fifty-six million, four hundred twenty thousand, four hundred eighty".