209681307533 has 2 divisors, whose sum is σ = 209681307534. Its totient is φ = 209681307532.

The previous prime is 209681307509. The next prime is 209681307551. The reversal of 209681307533 is 335703186902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 206918543689 + 2762763844 = 454883^2 + 52562^2 .

It is a cyclic number.

It is not a de Polignac number, because 209681307533 - 2³⁶ = 140961830797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209681307233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104840653766 + 104840653767.

It is an arithmetic number, because the mean of its divisors is an integer number (104840653767).

Almost surely, 2^209681307533 is an apocalyptic number.

It is an amenable number.

209681307533 is a deficient number, since it is larger than the sum of its proper divisors (1).

209681307533 is an equidigital number, since it uses as much as digits as its factorization.

209681307533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 816480, while the sum is 47.

The spelling of 209681307533 in words is "two hundred nine billion, six hundred eighty-one million, three hundred seven thousand, five hundred thirty-three".