21423420432 has 140 divisors (see below), whose sum is σ = 63559086720. Its totient is φ = 6989022144.

The previous prime is 21423420413. The next prime is 21423420437. The reversal of 21423420432 is 23402432412.

21423420432 is a `hidden beast` number, since 2 + 1 + 423 + 4 + 204 + 32 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21423420396 and 21423420405.

It is not an unprimeable number, because it can be changed into a prime (21423420437) by changing a digit.

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 27 ways as a sum of consecutive naturals, for example, 528669 + ... + 567747.

Almost surely, 2^21423420432 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 21423420432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31779543360).

21423420432 is an abundant number, since it is smaller than the sum of its proper divisors (42135666288).

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

21423420432 is an equidigital number, since it uses as much as digits as its factorization.

21423420432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39152 (or 39131 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 27.

Adding to 21423420432 its reverse (23402432412), we get a palindrome (44825852844).

The spelling of 21423420432 in words is "twenty-one billion, four hundred twenty-three million, four hundred twenty thousand, four hundred thirty-two".