21432420403 has 4 divisors (see below), whose sum is σ = 21500030880. Its totient is φ = 21364809928.

The previous prime is 21432420397. The next prime is 21432420407. The reversal of 21432420403 is 30402423412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21432420403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21432420407) 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 3 ways as a sum of consecutive naturals, for example, 33804763 + ... + 33805396.

It is an arithmetic number, because the mean of its divisors is an integer number (5375007720).

Almost surely, 2^21432420403 is an apocalyptic number.

21432420403 is a deficient number, since it is larger than the sum of its proper divisors (67610477).

21432420403 is an equidigital number, since it uses as much as digits as its factorization.

21432420403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67610476.

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

Adding to 21432420403 its reverse (30402423412), we get a palindrome (51834843815).

The spelling of 21432420403 in words is "twenty-one billion, four hundred thirty-two million, four hundred twenty thousand, four hundred three".