208218649 has 2 divisors, whose sum is σ = 208218650. Its totient is φ = 208218648.

The previous prime is 208218631. The next prime is 208218653. The reversal of 208218649 is 946812802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 130690624 + 77528025 = 11432^2 + 8805^2 .

It is a cyclic number.

It is not a de Polignac number, because 208218649 - 2⁹ = 208218137 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (208218679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104109324 + 104109325.

It is an arithmetic number, because the mean of its divisors is an integer number (104109325).

Almost surely, 2^208218649 is an apocalyptic number.

It is an amenable number.

208218649 is a deficient number, since it is larger than the sum of its proper divisors (1).

208218649 is an equidigital number, since it uses as much as digits as its factorization.

208218649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 208218649 is about 14429.7834010078. The cubic root of 208218649 is about 592.7067521319.

The spelling of 208218649 in words is "two hundred eight million, two hundred eighteen thousand, six hundred forty-nine".