21744205751240 has 128 divisors (see below), whose sum is σ = 57572484652800. Its totient is φ = 7235017251840.

The previous prime is 21744205751227. The next prime is 21744205751243. The reversal of 21744205751240 is 4215750244712.

It is a junction number, because it is equal to n+sod(n) for n = 21744205751191 and 21744205751200.

It is not an unprimeable number, because it can be changed into a prime (21744205751243) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1332275 + ... + 6727805.

It is an arithmetic number, because the mean of its divisors is an integer number (449785036350).

Almost surely, 2^{21744205751240} is an apocalyptic number.

21744205751240 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 21744205751240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28786242326400).

21744205751240 is an abundant number, since it is smaller than the sum of its proper divisors (35828278901560).

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

21744205751240 is a wasteful number, since it uses less digits than its factorization.

21744205751240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5395975 (or 5395971 counting only the distinct ones).

The product of its (nonzero) digits is 627200, while the sum is 44.

Adding to 21744205751240 its reverse (4215750244712), we get a palindrome (25959955995952).

The spelling of 21744205751240 in words is "twenty-one trillion, seven hundred forty-four billion, two hundred five million, seven hundred fifty-one thousand, two hundred forty".