208490677649 has 2 divisors, whose sum is σ = 208490677650. Its totient is φ = 208490677648.

The previous prime is 208490677573. The next prime is 208490677651. The reversal of 208490677649 is 946776094802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 190013169025 + 18477508624 = 435905^2 + 135932^2 .

It is a cyclic number.

It is not a de Polignac number, because 208490677649 - 2²⁴ = 208473900433 is a prime.

Together with 208490677651, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 208490677591 and 208490677600.

It is not a weakly prime, because it can be changed into another prime (208490677669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104245338824 + 104245338825.

It is an arithmetic number, because the mean of its divisors is an integer number (104245338825).

Almost surely, 2^208490677649 is an apocalyptic number.

It is an amenable number.

208490677649 is a deficient number, since it is larger than the sum of its proper divisors (1).

208490677649 is an equidigital number, since it uses as much as digits as its factorization.

208490677649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36578304, while the sum is 62.

The spelling of 208490677649 in words is "two hundred eight billion, four hundred ninety million, six hundred seventy-seven thousand, six hundred forty-nine".