1561806 has 12 divisors (see below), whose sum is σ = 3383952. Its totient is φ = 520596.

The previous prime is 1561801. The next prime is 1561817. The reversal of 1561806 is 6081651.

It is a self number, because there is not a number n which added to its sum of digits gives 1561806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 43366 + ... + 43401.

It is an arithmetic number, because the mean of its divisors is an integer number (281996).

2^1561806 is an apocalyptic number.

1561806 is an abundant number, since it is smaller than the sum of its proper divisors (1822146).

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

1561806 is a wasteful number, since it uses less digits than its factorization.

1561806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86775 (or 86772 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 1561806 is about 1249.7223691684. The cubic root of 1561806 is about 116.0225382287.

The spelling of 1561806 in words is "one million, five hundred sixty-one thousand, eight hundred six".