21425303520 has 240 divisors, whose sum is σ = 75787866000. Its totient is φ = 5700243456.

The previous prime is 21425303441. The next prime is 21425303561. The reversal of 21425303520 is 2530352412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 6465384 + ... + 6468696.

It is an arithmetic number, because the mean of its divisors is an integer number (315782775).

Almost surely, 2^21425303520 is an apocalyptic number.

21425303520 is a gapful number since it is divisible by the number (20) 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 21425303520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37893933000).

21425303520 is an abundant number, since it is smaller than the sum of its proper divisors (54362562480).

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

21425303520 is a wasteful number, since it uses less digits than its factorization.

21425303520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3839 (or 3822 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

Adding to 21425303520 its reverse (2530352412), we get a palindrome (23955655932).

The spelling of 21425303520 in words is "twenty-one billion, four hundred twenty-five million, three hundred three thousand, five hundred twenty".