21443415440 has 80 divisors (see below), whose sum is σ = 51103122048. Its totient is φ = 8363486208.

The previous prime is 21443415439. The next prime is 21443415473. The reversal of 21443415440 is 4451434412.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 21443415397 and 21443415406.

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, 2117429 + ... + 2127531.

Almost surely, 2^21443415440 is an apocalyptic number.

21443415440 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 21443415440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25551561024).

21443415440 is an abundant number, since it is smaller than the sum of its proper divisors (29659706608).

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

21443415440 is a wasteful number, since it uses less digits than its factorization.

21443415440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10776 (or 10770 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 32.

Adding to 21443415440 its reverse (4451434412), we get a palindrome (25894849852).

The spelling of 21443415440 in words is "twenty-one billion, four hundred forty-three million, four hundred fifteen thousand, four hundred forty".