21523435244 has 6 divisors (see below), whose sum is σ = 37666011684. Its totient is φ = 10761717620.

The previous prime is 21523435237. The next prime is 21523435249. The reversal of 21523435244 is 44253432512.

It is a happy number.

It is a super-2 number, since 2×21523435244² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21523435249) 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 as a sum of consecutive naturals, namely, 2690429402 + ... + 2690429409.

It is an arithmetic number, because the mean of its divisors is an integer number (6277668614).

Almost surely, 2^21523435244 is an apocalyptic number.

It is an amenable number.

21523435244 is a deficient number, since it is larger than the sum of its proper divisors (16142576440).

21523435244 is a wasteful number, since it uses less digits than its factorization.

21523435244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5380858815 (or 5380858813 counting only the distinct ones).

The product of its digits is 115200, while the sum is 35.

Adding to 21523435244 its reverse (44253432512), we get a palindrome (65776867756).

The spelling of 21523435244 in words is "twenty-one billion, five hundred twenty-three million, four hundred thirty-five thousand, two hundred forty-four".