920809 has 4 divisors (see below), whose sum is σ = 925060. Its totient is φ = 916560.

The previous prime is 920807. The next prime is 920827. The reversal of 920809 is 908029.

920809 = T₇₈₂ + T₇₈₃ + T₇₈₄.

It is a happy number.

920809 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 an emirpimes, since its reverse is a distinct semiprime: 908029 = 19 ⋅47791.

It can be written as a sum of positive squares in 2 ways, for example, as 451584 + 469225 = 672^2 + 685^2 .

It is a cyclic number.

It is not a de Polignac number, because 920809 - 2¹ = 920807 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 (920807) 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, 1782 + ... + 2239.

It is an arithmetic number, because the mean of its divisors is an integer number (231265).

2⁹²⁰⁸⁰⁹ is an apocalyptic number.

920809 is the 784-th centered triangular number.

It is an amenable number.

920809 is a deficient number, since it is larger than the sum of its proper divisors (4251).

920809 is a wasteful number, since it uses less digits than its factorization.

920809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4250.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 920809 is about 959.5879323960. The cubic root of 920809 is about 97.2873823988.

The spelling of 920809 in words is "nine hundred twenty thousand, eight hundred nine".