21505241244 has 24 divisors (see below), whose sum is σ = 50181416208. Its totient is φ = 7168053760.

The previous prime is 21505241161. The next prime is 21505241273. The reversal of 21505241244 is 44214250512.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 326764 + ... + 387020.

It is an arithmetic number, because the mean of its divisors is an integer number (2090892342).

Almost surely, 2^21505241244 is an apocalyptic number.

It is an amenable number.

21505241244 is an abundant number, since it is smaller than the sum of its proper divisors (28676174964).

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

21505241244 is a wasteful number, since it uses less digits than its factorization.

21505241244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90005 (or 90003 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 30.

Adding to 21505241244 its reverse (44214250512), we get a palindrome (65719491756).

The spelling of 21505241244 in words is "twenty-one billion, five hundred five million, two hundred forty-one thousand, two hundred forty-four".