1605906 has 40 divisors (see below), whose sum is σ = 3763584. Its totient is φ = 510840.

The previous prime is 1605889. The next prime is 1605907. The reversal of 1605906 is 6095061.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 1605906.

It is not an unprimeable number, because it can be changed into a prime (1605907) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3511 + ... + 3941.

2^1605906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1605906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1881792).

1605906 is an abundant number, since it is smaller than the sum of its proper divisors (2157678).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1605906 is a wasteful number, since it uses less digits than its factorization.

1605906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468 (or 459 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 1605906 is about 1267.2434651637. The cubic root of 1605906 is about 117.1044432273.

The spelling of 1605906 in words is "one million, six hundred five thousand, nine hundred six".