209042987 has 2 divisors, whose sum is σ = 209042988. Its totient is φ = 209042986.

The previous prime is 209042983. The next prime is 209042989. The reversal of 209042987 is 789240902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 209042987 - 2² = 209042983 is a prime.

Together with 209042989, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (209042983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104521493 + 104521494.

It is an arithmetic number, because the mean of its divisors is an integer number (104521494).

Almost surely, 2^209042987 is an apocalyptic number.

209042987 is a deficient number, since it is larger than the sum of its proper divisors (1).

209042987 is an equidigital number, since it uses as much as digits as its factorization.

209042987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 209042987 is about 14458.3189548440. The cubic root of 209042987 is about 593.4878978783.

The spelling of 209042987 in words is "two hundred nine million, forty-two thousand, nine hundred eighty-seven".