409689 has 18 divisors (see below), whose sum is σ = 689130. Its totient is φ = 233856.

The previous prime is 409657. The next prime is 409691. The reversal of 409689 is 986904.

It can be written as a sum of positive squares in only one way, i.e., 233289 + 176400 = 483^2 + 420^2 .

It is not a de Polignac number, because 409689 - 2⁵ = 409657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (409609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 24 + ... + 905.

It is an arithmetic number, because the mean of its divisors is an integer number (38285).

2⁴⁰⁹⁶⁸⁹ is an apocalyptic number.

409689 is a gapful number since it is divisible by the number (49) formed by its first and last digit.

It is an amenable number.

409689 is a deficient number, since it is larger than the sum of its proper divisors (279441).

409689 is a wasteful number, since it uses less digits than its factorization.

409689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 949 (or 939 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 409689 is about 640.0695274734. The cubic root of 409689 is about 74.2707998728.

The spelling of 409689 in words is "four hundred nine thousand, six hundred eighty-nine".