409861 has 2 divisors, whose sum is σ = 409862. Its totient is φ = 409860.

The previous prime is 409841. The next prime is 409867. The reversal of 409861 is 168904.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 245025 + 164836 = 495^2 + 406^2 .

It is a cyclic number.

It is not a de Polignac number, because 409861 - 2⁷ = 409733 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (409867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204930 + 204931.

It is an arithmetic number, because the mean of its divisors is an integer number (204931).

2⁴⁰⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

409861 is a deficient number, since it is larger than the sum of its proper divisors (1).

409861 is an equidigital number, since it uses as much as digits as its factorization.

409861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 409861 is about 640.2038737777. The cubic root of 409861 is about 74.2811921381.

The spelling of 409861 in words is "four hundred nine thousand, eight hundred sixty-one".