840258217 has 2 divisors, whose sum is σ = 840258218. Its totient is φ = 840258216.

The previous prime is 840258173. The next prime is 840258247. The reversal of 840258217 is 712852048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 584865856 + 255392361 = 24184^2 + 15981^2 .

It is a cyclic number.

It is not a de Polignac number, because 840258217 - 2¹¹ = 840256169 is a prime.

It is not a weakly prime, because it can be changed into another prime (840258247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420129108 + 420129109.

It is an arithmetic number, because the mean of its divisors is an integer number (420129109).

Almost surely, 2^840258217 is an apocalyptic number.

It is an amenable number.

840258217 is a deficient number, since it is larger than the sum of its proper divisors (1).

840258217 is an equidigital number, since it uses as much as digits as its factorization.

840258217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35840, while the sum is 37.

The square root of 840258217 is about 28987.2078165525. The cubic root of 840258217 is about 943.6354678080.

The spelling of 840258217 in words is "eight hundred forty million, two hundred fifty-eight thousand, two hundred seventeen".