900805 has 4 divisors (see below), whose sum is σ = 1080972. Its totient is φ = 720640.

The previous prime is 900803. The next prime is 900817. The reversal of 900805 is 508009.

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 128164 + 772641 = 358^2 + 879^2 .

It is not a de Polignac number, because 900805 - 2¹ = 900803 is a prime.

It is a super-2 number, since 2×900805² = 1622899296050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (900803) 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 3 ways as a sum of consecutive naturals, for example, 90076 + ... + 90085.

It is an arithmetic number, because the mean of its divisors is an integer number (270243).

2⁹⁰⁰⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

900805 is a deficient number, since it is larger than the sum of its proper divisors (180167).

900805 is a wasteful number, since it uses less digits than its factorization.

900805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180166.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 900805 is about 949.1074754737. The cubic root of 900805 is about 96.5777157696.

The spelling of 900805 in words is "nine hundred thousand, eight hundred five".