21231203533 has 2 divisors, whose sum is σ = 21231203534. Its totient is φ = 21231203532.

The previous prime is 21231203509. The next prime is 21231203549. The reversal of 21231203533 is 33530213212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13386027204 + 7845176329 = 115698^2 + 88573^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231203533 - 2⁵ = 21231203501 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21231203498 and 21231203507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231203563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615601766 + 10615601767.

It is an arithmetic number, because the mean of its divisors is an integer number (10615601767).

Almost surely, 2^21231203533 is an apocalyptic number.

It is an amenable number.

21231203533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231203533 is an equidigital number, since it uses as much as digits as its factorization.

21231203533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 25.

Adding to 21231203533 its reverse (33530213212), we get a palindrome (54761416745).

The spelling of 21231203533 in words is "twenty-one billion, two hundred thirty-one million, two hundred three thousand, five hundred thirty-three".