21242340420 has 192 divisors, whose sum is σ = 68650745856. Its totient is φ = 4807434240.

The previous prime is 21242340373. The next prime is 21242340439. The reversal of 21242340420 is 2404324212.

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 63 ways as a sum of consecutive naturals, for example, 21966777 + ... + 21967743.

It is an arithmetic number, because the mean of its divisors is an integer number (357555968).

Almost surely, 2^21242340420 is an apocalyptic number.

21242340420 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 21242340420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34325372928).

21242340420 is an abundant number, since it is smaller than the sum of its proper divisors (47408405436).

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

21242340420 is a wasteful number, since it uses less digits than its factorization.

21242340420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1450 (or 1448 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21242340420 its reverse (2404324212), we get a palindrome (23646664632).

The spelling of 21242340420 in words is "twenty-one billion, two hundred forty-two million, three hundred forty thousand, four hundred twenty".