21343423520 has 96 divisors (see below), whose sum is σ = 53870443200. Its totient is φ = 7967241216.

The previous prime is 21343423511. The next prime is 21343423547. The reversal of 21343423520 is 2532434312.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 151286 + ... + 256074.

It is an arithmetic number, because the mean of its divisors is an integer number (561150450).

Almost surely, 2^21343423520 is an apocalyptic number.

21343423520 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 21343423520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26935221600).

21343423520 is an abundant number, since it is smaller than the sum of its proper divisors (32527019680).

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

21343423520 is a wasteful number, since it uses less digits than its factorization.

21343423520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104890 (or 104882 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 29.

Adding to 21343423520 its reverse (2532434312), we get a palindrome (23875857832).

The spelling of 21343423520 in words is "twenty-one billion, three hundred forty-three million, four hundred twenty-three thousand, five hundred twenty".