21203313231 has 4 divisors (see below), whose sum is σ = 28271084312. Its totient is φ = 14135542152.

The previous prime is 21203313217. The next prime is 21203313233. The reversal of 21203313231 is 13231330212.

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

It is not a de Polignac number, because 21203313231 - 2⁶ = 21203313167 is a prime.

It is a super-2 number, since 2×21203313231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21203313198 and 21203313207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203313233) 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, 3533885536 + ... + 3533885541.

It is an arithmetic number, because the mean of its divisors is an integer number (7067771078).

Almost surely, 2^21203313231 is an apocalyptic number.

21203313231 is a deficient number, since it is larger than the sum of its proper divisors (7067771081).

21203313231 is an equidigital number, since it uses as much as digits as its factorization.

21203313231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7067771080.

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21203313231 its reverse (13231330212), we get a palindrome (34434643443).

The spelling of 21203313231 in words is "twenty-one billion, two hundred three million, three hundred thirteen thousand, two hundred thirty-one".