21213430504420 has 192 divisors, whose sum is σ = 57367828611072. Its totient is φ = 6394718016000.

The previous prime is 21213430504351. The next prime is 21213430504421. The reversal of 21213430504420 is 2440503431212.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (21213430504421) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 77249479 + ... + 77523601.

It is an arithmetic number, because the mean of its divisors is an integer number (298790774016).

Almost surely, 2^{21213430504420} is an apocalyptic number.

21213430504420 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 21213430504420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28683914305536).

21213430504420 is an abundant number, since it is smaller than the sum of its proper divisors (36154398106652).

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

21213430504420 is a wasteful number, since it uses less digits than its factorization.

21213430504420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275802 (or 275800 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 31.

Adding to 21213430504420 its reverse (2440503431212), we get a palindrome (23653933935632).

The spelling of 21213430504420 in words is "twenty-one trillion, two hundred thirteen billion, four hundred thirty million, five hundred four thousand, four hundred twenty".