21203403431 has 6 divisors (see below), whose sum is σ = 24665183640. Its totient is φ = 18174345756.

The previous prime is 21203403401. The next prime is 21203403437. The reversal of 21203403431 is 13430430212.

It is not a de Polignac number, because 21203403431 - 2¹⁴ = 21203387047 is a prime.

It is a super-3 number, since 3×21203403431³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21203403397 and 21203403406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203403437) 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 5 ways as a sum of consecutive naturals, for example, 216361211 + ... + 216361308.

It is an arithmetic number, because the mean of its divisors is an integer number (4110863940).

Almost surely, 2^21203403431 is an apocalyptic number.

21203403431 is a deficient number, since it is larger than the sum of its proper divisors (3461780209).

21203403431 is an equidigital number, since it uses as much as digits as its factorization.

21203403431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432722533 (or 432722526 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

Adding to 21203403431 its reverse (13430430212), we get a palindrome (34633833643).

The spelling of 21203403431 in words is "twenty-one billion, two hundred three million, four hundred three thousand, four hundred thirty-one".