21265301244 has 96 divisors (see below), whose sum is σ = 55740142080. Its totient is φ = 6253977600.

The previous prime is 21265301191. The next prime is 21265301261. The reversal of 21265301244 is 44210356212.

It is a congruent number.

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, 1034337 + ... + 1054695.

It is an arithmetic number, because the mean of its divisors is an integer number (580626480).

Almost surely, 2^21265301244 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 21265301244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27870071040).

21265301244 is an abundant number, since it is smaller than the sum of its proper divisors (34474840836).

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

21265301244 is a wasteful number, since it uses less digits than its factorization.

21265301244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20611 (or 20609 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21265301244 its reverse (44210356212), we get a palindrome (65475657456).

The spelling of 21265301244 in words is "twenty-one billion, two hundred sixty-five million, three hundred one thousand, two hundred forty-four".