823561 has 8 divisors (see below), whose sum is σ = 874944. Its totient is φ = 773520.

The previous prime is 823553. The next prime is 823573. The reversal of 823561 is 165328.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 823561 - 2³ = 823553 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (823541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1110 + ... + 1696.

It is an arithmetic number, because the mean of its divisors is an integer number (109368).

823561 is a Friedman number, since it can be written as 6*3+(5+2)^(8-1), using all its digits and the basic arithmetic operations.

2⁸²³⁵⁶¹ is an apocalyptic number.

It is an amenable number.

823561 is a deficient number, since it is larger than the sum of its proper divisors (51383).

823561 is a wasteful number, since it uses less digits than its factorization.

823561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671.

The product of its digits is 1440, while the sum is 25.

The square root of 823561 is about 907.5026170761. The cubic root of 823561 is about 93.7343108560.

Adding to 823561 its reverse (165328), we get a palindrome (988889).

The spelling of 823561 in words is "eight hundred twenty-three thousand, five hundred sixty-one".