209710566641 has 2 divisors, whose sum is σ = 209710566642. Its totient is φ = 209710566640.

The previous prime is 209710566623. The next prime is 209710566649. The reversal of 209710566641 is 146665017902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126590793616 + 83119773025 = 355796^2 + 288305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209710566641 is a prime.

It is not a weakly prime, because it can be changed into another prime (209710566649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104855283320 + 104855283321.

It is an arithmetic number, because the mean of its divisors is an integer number (104855283321).

Almost surely, 2^209710566641 is an apocalyptic number.

It is an amenable number.

209710566641 is a deficient number, since it is larger than the sum of its proper divisors (1).

209710566641 is an equidigital number, since it uses as much as digits as its factorization.

209710566641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 47.

The spelling of 209710566641 in words is "two hundred nine billion, seven hundred ten million, five hundred sixty-six thousand, six hundred forty-one".