209545643297 has 2 divisors, whose sum is σ = 209545643298. Its totient is φ = 209545643296.

The previous prime is 209545643221. The next prime is 209545643303. The reversal of 209545643297 is 792346545902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208706440336 + 839202961 = 456844^2 + 28969^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209545643297 is a prime.

It is a super-2 number, since 2×209545643297² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (209545642297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104772821648 + 104772821649.

It is an arithmetic number, because the mean of its divisors is an integer number (104772821649).

Almost surely, 2^209545643297 is an apocalyptic number.

It is an amenable number.

209545643297 is a deficient number, since it is larger than the sum of its proper divisors (1).

209545643297 is an equidigital number, since it uses as much as digits as its factorization.

209545643297 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16329600, while the sum is 56.

The spelling of 209545643297 in words is "two hundred nine billion, five hundred forty-five million, six hundred forty-three thousand, two hundred ninety-seven".