805561 has 4 divisors (see below), whose sum is σ = 812032. Its totient is φ = 799092.

The previous prime is 805559. The next prime is 805573. The reversal of 805561 is 165508.

805561 = T₄₃ + T₄₄ + ... + T₁₆₉.

805561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 805561 - 2¹ = 805559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (805501) 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, 3045 + ... + 3298.

It is an arithmetic number, because the mean of its divisors is an integer number (203008).

2⁸⁰⁵⁵⁶¹ is an apocalyptic number.

It is an amenable number.

805561 is a deficient number, since it is larger than the sum of its proper divisors (6471).

805561 is a wasteful number, since it uses less digits than its factorization.

805561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6470.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 805561 is about 897.5305008745. The cubic root of 805561 is about 93.0463791484.

The spelling of 805561 in words is "eight hundred five thousand, five hundred sixty-one".