209971241 has 2 divisors, whose sum is σ = 209971242. Its totient is φ = 209971240.

The previous prime is 209971217. The next prime is 209971243. The reversal of 209971241 is 142179902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180768025 + 29203216 = 13445^2 + 5404^2 .

It is a cyclic number.

It is not a de Polignac number, because 209971241 - 2²² = 205776937 is a prime.

Together with 209971243, 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 (209971243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104985620 + 104985621.

It is an arithmetic number, because the mean of its divisors is an integer number (104985621).

Almost surely, 2^209971241 is an apocalyptic number.

It is an amenable number.

209971241 is a deficient number, since it is larger than the sum of its proper divisors (1).

209971241 is an equidigital number, since it uses as much as digits as its factorization.

209971241 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 209971241 is about 14490.3844324435. The cubic root of 209971241 is about 594.3650605056.

The spelling of 209971241 in words is "two hundred nine million, nine hundred seventy-one thousand, two hundred forty-one".