21449305540 has 96 divisors (see below), whose sum is σ = 48844736640. Its totient is φ = 7865088000.

The previous prime is 21449305487. The next prime is 21449305597. The reversal of 21449305540 is 4550394412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21449305540.

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, 43684695 + ... + 43685185.

It is an arithmetic number, because the mean of its divisors is an integer number (508799340).

Almost surely, 2^21449305540 is an apocalyptic number.

21449305540 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 21449305540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24422368320).

21449305540 is an abundant number, since it is smaller than the sum of its proper divisors (27395431100).

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

21449305540 is a wasteful number, since it uses less digits than its factorization.

21449305540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333 (or 1331 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

Adding to 21449305540 its reverse (4550394412), we get a palindrome (25999699952).

The spelling of 21449305540 in words is "twenty-one billion, four hundred forty-nine million, three hundred five thousand, five hundred forty".