21240430432 has 96 divisors (see below), whose sum is σ = 46251233280. Its totient is φ = 9541808640.

The previous prime is 21240430427. The next prime is 21240430433. The reversal of 21240430432 is 23403404212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21240430397 and 21240430406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240430433) 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 in 15 ways as a sum of consecutive naturals, for example, 2328793 + ... + 2337895.

It is an arithmetic number, because the mean of its divisors is an integer number (481783680).

Almost surely, 2^21240430432 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 21240430432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23125616640).

21240430432 is an abundant number, since it is smaller than the sum of its proper divisors (25010802848).

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

21240430432 is a wasteful number, since it uses less digits than its factorization.

21240430432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9276 (or 9268 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21240430432 its reverse (23403404212), we get a palindrome (44643834644).

The spelling of 21240430432 in words is "twenty-one billion, two hundred forty million, four hundred thirty thousand, four hundred thirty-two".