21344240420 has 24 divisors (see below), whose sum is σ = 44828347200. Its totient is φ = 8536659552.

The previous prime is 21344240399. The next prime is 21344240447. The reversal of 21344240420 is 2404244312.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21344240420.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116411 + ... + 237149.

It is an arithmetic number, because the mean of its divisors is an integer number (1867847800).

Almost surely, 2^21344240420 is an apocalyptic number.

21344240420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21344240420 is an abundant number, since it is smaller than the sum of its proper divisors (23484106780).

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

21344240420 is a wasteful number, since it uses less digits than its factorization.

21344240420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129587 (or 129585 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 26.

Adding to 21344240420 its reverse (2404244312), we get a palindrome (23748484732).

The spelling of 21344240420 in words is "twenty-one billion, three hundred forty-four million, two hundred forty thousand, four hundred twenty".