21525122424 has 256 divisors, whose sum is σ = 64700052480. Its totient is φ = 5900083200.

The previous prime is 21525122393. The next prime is 21525122471. The reversal of 21525122424 is 42422152512.

It is a junction number, because it is equal to n+sod(n) for n = 21525122391 and 21525122400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12320319 + ... + 12322065.

It is an arithmetic number, because the mean of its divisors is an integer number (252734580).

Almost surely, 2^21525122424 is an apocalyptic number.

21525122424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21525122424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32350026240).

21525122424 is an abundant number, since it is smaller than the sum of its proper divisors (43174930056).

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

21525122424 is a wasteful number, since it uses less digits than its factorization.

21525122424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910 (or 1906 counting only the distinct ones).

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

Adding to 21525122424 its reverse (42422152512), we get a palindrome (63947274936).

The spelling of 21525122424 in words is "twenty-one billion, five hundred twenty-five million, one hundred twenty-two thousand, four hundred twenty-four".