21244220550 has 144 divisors (see below), whose sum is σ = 66461148000. Its totient is φ = 4764165120.

The previous prime is 21244220539. The next prime is 21244220597. The reversal of 21244220550 is 5502244212.

21244220550 is a `hidden beast` number, since 2 + 12 + 442 + 205 + 5 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 103326 + ... + 230574.

It is an arithmetic number, because the mean of its divisors is an integer number (461535750).

Almost surely, 2^21244220550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21244220550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33230574000).

21244220550 is an abundant number, since it is smaller than the sum of its proper divisors (45216927450).

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

21244220550 is a wasteful number, since it uses less digits than its factorization.

21244220550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127327 (or 127319 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 27.

Adding to 21244220550 its reverse (5502244212), we get a palindrome (26746464762).

The spelling of 21244220550 in words is "twenty-one billion, two hundred forty-four million, two hundred twenty thousand, five hundred fifty".