21305431003 has 4 divisors (see below), whose sum is σ = 21605507568. Its totient is φ = 21005354440.

The previous prime is 21305430997. The next prime is 21305431087. The reversal of 21305431003 is 30013450312.

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

It is a cyclic number.

It is not a de Polignac number, because 21305431003 - 2¹⁷ = 21305299931 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21305431403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 150038176 + ... + 150038317.

It is an arithmetic number, because the mean of its divisors is an integer number (5401376892).

Almost surely, 2^21305431003 is an apocalyptic number.

21305431003 is a deficient number, since it is larger than the sum of its proper divisors (300076565).

21305431003 is an equidigital number, since it uses as much as digits as its factorization.

21305431003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300076564.

The product of its (nonzero) digits is 1080, while the sum is 22.

Adding to 21305431003 its reverse (30013450312), we get a palindrome (51318881315).

The spelling of 21305431003 in words is "twenty-one billion, three hundred five million, four hundred thirty-one thousand, three".