209685493 has 2 divisors, whose sum is σ = 209685494. Its totient is φ = 209685492.

The previous prime is 209685467. The next prime is 209685517. The reversal of 209685493 is 394586902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185014404 + 24671089 = 13602^2 + 4967^2 .

It is a cyclic number.

It is not a de Polignac number, because 209685493 - 2²⁵ = 176131061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209685403) 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 as a sum of consecutive naturals, namely, 104842746 + 104842747.

It is an arithmetic number, because the mean of its divisors is an integer number (104842747).

Almost surely, 2^209685493 is an apocalyptic number.

It is an amenable number.

209685493 is a deficient number, since it is larger than the sum of its proper divisors (1).

209685493 is an equidigital number, since it uses as much as digits as its factorization.

209685493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 466560, while the sum is 46.

The square root of 209685493 is about 14480.5211577484. The cubic root of 209685493 is about 594.0953160575.

The spelling of 209685493 in words is "two hundred nine million, six hundred eighty-five thousand, four hundred ninety-three".