21203333231 has 2 divisors, whose sum is σ = 21203333232. Its totient is φ = 21203333230.

The previous prime is 21203333213. The next prime is 21203333269. The reversal of 21203333231 is 13233330212.

Together with previous prime (21203333213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21203333231 - 2⁶ = 21203333167 is a prime.

It is a super-2 number, since 2×21203333231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21203333197 and 21203333206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203333131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601666615 + 10601666616.

It is an arithmetic number, because the mean of its divisors is an integer number (10601666616).

Almost surely, 2^21203333231 is an apocalyptic number.

21203333231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203333231 is an equidigital number, since it uses as much as digits as its factorization.

21203333231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 23.

Adding to 21203333231 its reverse (13233330212), we get a palindrome (34436663443).

The spelling of 21203333231 in words is "twenty-one billion, two hundred three million, three hundred thirty-three thousand, two hundred thirty-one".