1906409 has 4 divisors (see below), whose sum is σ = 1912404. Its totient is φ = 1900416.

The previous prime is 1906393. The next prime is 1906417. The reversal of 1906409 is 9046091.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 336400 + 1570009 = 580^2 + 1253^2 .

It is a cyclic number.

It is not a de Polignac number, because 1906409 - 2⁴ = 1906393 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1906439) 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, 2492 + ... + 3165.

It is an arithmetic number, because the mean of its divisors is an integer number (478101).

2^1906409 is an apocalyptic number.

It is an amenable number.

1906409 is a deficient number, since it is larger than the sum of its proper divisors (5995).

1906409 is an equidigital number, since it uses as much as digits as its factorization.

1906409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5994.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 1906409 is about 1380.7277066822. The cubic root of 1906409 is about 123.9953388813.

The spelling of 1906409 in words is "one million, nine hundred six thousand, four hundred nine".