1705218121 has 2 divisors, whose sum is σ = 1705218122. Its totient is φ = 1705218120.

The previous prime is 1705218103. The next prime is 1705218161. The reversal of 1705218121 is 1218125071.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1686252096 + 18966025 = 41064^2 + 4355^2 .

It is a cyclic number.

It is not a de Polignac number, because 1705218121 - 2⁷ = 1705217993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1705218121.

It is not a weakly prime, because it can be changed into another prime (1705218161) 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, 852609060 + 852609061.

It is an arithmetic number, because the mean of its divisors is an integer number (852609061).

Almost surely, 2^1705218121 is an apocalyptic number.

It is an amenable number.

1705218121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1705218121 is an equidigital number, since it uses as much as digits as its factorization.

1705218121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 28.

The square root of 1705218121 is about 41294.2867840092. The cubic root of 1705218121 is about 1194.7030700784.

The spelling of 1705218121 in words is "one billion, seven hundred five million, two hundred eighteen thousand, one hundred twenty-one".