21424135824 has 480 divisors, whose sum is σ = 80580398080. Its totient is φ = 5351256576.

The previous prime is 21424135823. The next prime is 21424135861. The reversal of 21424135824 is 42853142412.

21424135824 is a `hidden beast` number, since 21 + 42 + 4 + 13 + 582 + 4 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21424135823) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 6720759 + ... + 6723945.

Almost surely, 2^21424135824 is an apocalyptic number.

21424135824 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 21424135824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40290199040).

21424135824 is an abundant number, since it is smaller than the sum of its proper divisors (59156262256).

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

21424135824 is a wasteful number, since it uses less digits than its factorization.

21424135824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3249 (or 3231 counting only the distinct ones).

The product of its digits is 61440, while the sum is 36.

The spelling of 21424135824 in words is "twenty-one billion, four hundred twenty-four million, one hundred thirty-five thousand, eight hundred twenty-four".