21505234352 has 80 divisors (see below), whose sum is σ = 48215872320. Its totient is φ = 9101528064.

The previous prime is 21505234343. The next prime is 21505234357. The reversal of 21505234352 is 25343250512.

It is not an unprimeable number, because it can be changed into a prime (21505234357) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 3867158 + ... + 3872714.

It is an arithmetic number, because the mean of its divisors is an integer number (602698404).

Almost surely, 2^21505234352 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 21505234352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24107936160).

21505234352 is an abundant number, since it is smaller than the sum of its proper divisors (26710637968).

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

21505234352 is a wasteful number, since it uses less digits than its factorization.

21505234352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5998 (or 5992 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 32.

Adding to 21505234352 its reverse (25343250512), we get a palindrome (46848484864).

The spelling of 21505234352 in words is "twenty-one billion, five hundred five million, two hundred thirty-four thousand, three hundred fifty-two".