21440243040 has 144 divisors (see below), whose sum is σ = 70601651568. Its totient is φ = 5468750848.

The previous prime is 21440242969. The next prime is 21440243053. The reversal of 21440243040 is 4034204412.

It is a happy number.

It is a super-2 number, since 2×21440243040² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21440243040.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 211702 + ... + 296138.

It is an arithmetic number, because the mean of its divisors is an integer number (490289247).

Almost surely, 2^21440243040 is an apocalyptic number.

21440243040 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 21440243040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35300825784).

21440243040 is an abundant number, since it is smaller than the sum of its proper divisors (49161408528).

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

21440243040 is a wasteful number, since it uses less digits than its factorization.

21440243040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84501 (or 84470 counting only the distinct ones).

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

Adding to 21440243040 its reverse (4034204412), we get a palindrome (25474447452).

The spelling of 21440243040 in words is "twenty-one billion, four hundred forty million, two hundred forty-three thousand, forty".