21424434552 has 320 divisors, whose sum is σ = 67159065600. Its totient is φ = 6348948480.

The previous prime is 21424434461. The next prime is 21424434553. The reversal of 21424434552 is 25543442412.

21424434552 is a `hidden beast` number, since 21 + 4 + 244 + 345 + 52 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424434553) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 14683599 + ... + 14685057.

It is an arithmetic number, because the mean of its divisors is an integer number (209872080).

Almost surely, 2^21424434552 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 21424434552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33579532800).

21424434552 is an abundant number, since it is smaller than the sum of its proper divisors (45734631048).

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

21424434552 is a wasteful number, since it uses less digits than its factorization.

21424434552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1568 (or 1555 counting only the distinct ones).

The product of its digits is 153600, while the sum is 36.

Adding to 21424434552 its reverse (25543442412), we get a palindrome (46967876964).

The spelling of 21424434552 in words is "twenty-one billion, four hundred twenty-four million, four hundred thirty-four thousand, five hundred fifty-two".