21213463680 has 384 divisors, whose sum is σ = 77946278400. Its totient is φ = 5446932480.

The previous prime is 21213463679. The next prime is 21213463693. The reversal of 21213463680 is 8636431212.

21213463680 is a `hidden beast` number, since 2 + 1 + 2 + 13 + 4 + 636 + 8 + 0 = 666.

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

It is a super-2 number, since 2×21213463680² (a number of 21 digits) contains 22 as substring.

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 47 ways as a sum of consecutive naturals, for example, 106600221 + ... + 106600419.

It is an arithmetic number, because the mean of its divisors is an integer number (202985100).

Almost surely, 2^21213463680 is an apocalyptic number.

21213463680 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 21213463680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38973139200).

21213463680 is an abundant number, since it is smaller than the sum of its proper divisors (56732814720).

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

21213463680 is an equidigital number, since it uses as much as digits as its factorization.

21213463680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

Adding to 21213463680 its reverse (8636431212), we get a palindrome (29849894892).

The spelling of 21213463680 in words is "twenty-one billion, two hundred thirteen million, four hundred sixty-three thousand, six hundred eighty".