21131440044 has 96 divisors (see below), whose sum is σ = 58113291264. Its totient is φ = 5891857920.

The previous prime is 21131440039. The next prime is 21131440061. The reversal of 21131440044 is 44004413112.

It is a junction number, because it is equal to n+sod(n) for n = 21131439996 and 21131440023.

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, 517437 + ... + 556779.

It is an arithmetic number, because the mean of its divisors is an integer number (605346784).

Almost surely, 2^21131440044 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131440044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29056645632).

21131440044 is an abundant number, since it is smaller than the sum of its proper divisors (36981851220).

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

21131440044 is a wasteful number, since it uses less digits than its factorization.

21131440044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39687 (or 39685 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21131440044 its reverse (44004413112), we get a palindrome (65135853156).

The spelling of 21131440044 in words is "twenty-one billion, one hundred thirty-one million, four hundred forty thousand, forty-four".