21144441440 has 24 divisors (see below), whose sum is σ = 49953743280. Its totient is φ = 8457776512.

The previous prime is 21144441431. The next prime is 21144441449. The reversal of 21144441440 is 4414444112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21144441431) and next prime (21144441449).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144441449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66076220 + ... + 66076539.

It is an arithmetic number, because the mean of its divisors is an integer number (2081405970).

Almost surely, 2^21144441440 is an apocalyptic number.

21144441440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144441440 is an abundant number, since it is smaller than the sum of its proper divisors (28809301840).

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

21144441440 is a wasteful number, since it uses less digits than its factorization.

21144441440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132152774 (or 132152766 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 29.

Adding to 21144441440 its reverse (4414444112), we get a palindrome (25558885552).

The spelling of 21144441440 in words is "twenty-one billion, one hundred forty-four million, four hundred forty-one thousand, four hundred forty".