21243413420 has 24 divisors (see below), whose sum is σ = 45148655664. Its totient is φ = 8394986816.

The previous prime is 21243413351. The next prime is 21243413447. The reversal of 21243413420 is 2431434212.

It is a super-2 number, since 2×21243413420² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21243413420.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6396959 + ... + 6400278.

It is an arithmetic number, because the mean of its divisors is an integer number (1881193986).

Almost surely, 2^21243413420 is an apocalyptic number.

21243413420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21243413420 is an abundant number, since it is smaller than the sum of its proper divisors (23905242244).

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

21243413420 is a wasteful number, since it uses less digits than its factorization.

21243413420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12797329 (or 12797327 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21243413420 its reverse (2431434212), we get a palindrome (23674847632).

The spelling of 21243413420 in words is "twenty-one billion, two hundred forty-three million, four hundred thirteen thousand, four hundred twenty".