690409 has 4 divisors (see below), whose sum is σ = 697216. Its totient is φ = 683604.

The previous prime is 690407. The next prime is 690419. The reversal of 690409 is 904096.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 690409 - 2¹ = 690407 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (690407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3249 + ... + 3454.

It is an arithmetic number, because the mean of its divisors is an integer number (174304).

2⁶⁹⁰⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

690409 is a deficient number, since it is larger than the sum of its proper divisors (6807).

690409 is a wasteful number, since it uses less digits than its factorization.

690409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6806.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 690409 is about 830.9085388898. The cubic root of 690409 is about 88.3830154439.

The spelling of 690409 in words is "six hundred ninety thousand, four hundred nine".