21444313240 has 128 divisors (see below), whose sum is σ = 57165004800. Its totient is φ = 7084707840.

The previous prime is 21444313193. The next prime is 21444313337. The reversal of 21444313240 is 4231344412.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21444313199 and 21444313208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2069352 + ... + 2079688.

It is an arithmetic number, because the mean of its divisors is an integer number (446601600).

Almost surely, 2^21444313240 is an apocalyptic number.

21444313240 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 21444313240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28582502400).

21444313240 is an abundant number, since it is smaller than the sum of its proper divisors (35720691560).

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

21444313240 is a wasteful number, since it uses less digits than its factorization.

21444313240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10625 (or 10621 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

Adding to 21444313240 its reverse (4231344412), we get a palindrome (25675657652).

The spelling of 21444313240 in words is "twenty-one billion, four hundred forty-four million, three hundred thirteen thousand, two hundred forty".