1685521 has 2 divisors, whose sum is σ = 1685522. Its totient is φ = 1685520.

The previous prime is 1685503. The next prime is 1685527. The reversal of 1685521 is 1255861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1354896 + 330625 = 1164^2 + 575^2 .

It is an emirp because it is prime and its reverse (1255861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1685521 - 2¹³ = 1677329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1685521.

It is not a weakly prime, because it can be changed into another prime (1685527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842760 + 842761.

It is an arithmetic number, because the mean of its divisors is an integer number (842761).

2^1685521 is an apocalyptic number.

It is an amenable number.

1685521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685521 is an equidigital number, since it uses as much as digits as its factorization.

1685521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 28.

The square root of 1685521 is about 1298.2761647662. The cubic root of 1685521 is about 119.0085204454.

The spelling of 1685521 in words is "one million, six hundred eighty-five thousand, five hundred twenty-one".