209494387 has 2 divisors, whose sum is σ = 209494388. Its totient is φ = 209494386.

The previous prime is 209494381. The next prime is 209494391. The reversal of 209494387 is 783494902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 209494387 - 2¹⁵ = 209461619 is a prime.

It is not a weakly prime, because it can be changed into another prime (209494381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104747193 + 104747194.

It is an arithmetic number, because the mean of its divisors is an integer number (104747194).

Almost surely, 2^209494387 is an apocalyptic number.

209494387 is a deficient number, since it is larger than the sum of its proper divisors (1).

209494387 is an equidigital number, since it uses as much as digits as its factorization.

209494387 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 46.

The square root of 209494387 is about 14473.9209269638. The cubic root of 209494387 is about 593.9147763246.

The spelling of 209494387 in words is "two hundred nine million, four hundred ninety-four thousand, three hundred eighty-seven".