1685861 has 2 divisors, whose sum is σ = 1685862. Its totient is φ = 1685860.

The previous prime is 1685837. The next prime is 1685863.

1685861 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1677025 + 8836 = 1295^2 + 94^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1685861 - 2¹⁸ = 1423717 is a prime.

It is a super-2 number, since 2×1685861² = 5684254622642, which contains 22 as substring.

Together with 1685863, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1685863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842930 + 842931.

It is an arithmetic number, because the mean of its divisors is an integer number (842931).

2^1685861 is an apocalyptic number.

It is an amenable number.

1685861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685861 is an equidigital number, since it uses as much as digits as its factorization.

1685861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 35.

The square root of 1685861 is about 1298.4071010280. The cubic root of 1685861 is about 119.0165219627.

The spelling of 1685861 in words is "one million, six hundred eighty-five thousand, eight hundred sixty-one".