209498197697 has 2 divisors, whose sum is σ = 209498197698. Its totient is φ = 209498197696.

The previous prime is 209498197679. The next prime is 209498197703. The reversal of 209498197697 is 796791894902.

Together with previous prime (209498197679) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160711990321 + 48786207376 = 400889^2 + 220876^2 .

It is a cyclic number.

It is not a de Polignac number, because 209498197697 - 2⁶ = 209498197633 is a prime.

It is a super-2 number, since 2×209498197697² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 209498197697.

It is not a weakly prime, because it can be changed into another prime (209498197627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104749098848 + 104749098849.

It is an arithmetic number, because the mean of its divisors is an integer number (104749098849).

Almost surely, 2^209498197697 is an apocalyptic number.

It is an amenable number.

209498197697 is a deficient number, since it is larger than the sum of its proper divisors (1).

209498197697 is an equidigital number, since it uses as much as digits as its factorization.

209498197697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 123451776, while the sum is 71.

The spelling of 209498197697 in words is "two hundred nine billion, four hundred ninety-eight million, one hundred ninety-seven thousand, six hundred ninety-seven".