1606405 has 8 divisors (see below), whose sum is σ = 1947384. Its totient is φ = 1272000.

The previous prime is 1606403. The next prime is 1606427. The reversal of 1606405 is 5046061.

It can be written as a sum of positive squares in 4 ways, for example, as 199809 + 1406596 = 447^2 + 1186^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1606405 - 2¹ = 1606403 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1606403) 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 7 ways as a sum of consecutive naturals, for example, 1086 + ... + 2095.

It is an arithmetic number, because the mean of its divisors is an integer number (243423).

2^1606405 is an apocalyptic number.

It is an amenable number.

1606405 is a deficient number, since it is larger than the sum of its proper divisors (340979).

1606405 is a wasteful number, since it uses less digits than its factorization.

1606405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3287.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1606405 is about 1267.4403339014. The cubic root of 1606405 is about 117.1165711820.

The spelling of 1606405 in words is "one million, six hundred six thousand, four hundred five".