397205209 has 2 divisors, whose sum is σ = 397205210. Its totient is φ = 397205208.

The previous prime is 397205173. The next prime is 397205213. The reversal of 397205209 is 902502793.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 377447184 + 19758025 = 19428^2 + 4445^2 .

It is a cyclic number.

It is not a de Polignac number, because 397205209 - 2¹⁷ = 397074137 is a prime.

It is not a weakly prime, because it can be changed into another prime (397205219) 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, 198602604 + 198602605.

It is an arithmetic number, because the mean of its divisors is an integer number (198602605).

Almost surely, 2^397205209 is an apocalyptic number.

It is an amenable number.

397205209 is a deficient number, since it is larger than the sum of its proper divisors (1).

397205209 is an equidigital number, since it uses as much as digits as its factorization.

397205209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 397205209 is about 19930.0077521310. The cubic root of 397205209 is about 735.0862712068.

The spelling of 397205209 in words is "three hundred ninety-seven million, two hundred five thousand, two hundred nine".