823638869 has 4 divisors (see below), whose sum is σ = 823711596. Its totient is φ = 823566144.

The previous prime is 823638863. The next prime is 823638913. The reversal of 823638869 is 968836328.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 223143844 + 600495025 = 14938^2 + 24505^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-823638869 is a prime.

It is a super-2 number, since 2×823638869² = 1356761973055198322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 823638869.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (823638863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15314 + ... + 43379.

It is an arithmetic number, because the mean of its divisors is an integer number (205927899).

Almost surely, 2^823638869 is an apocalyptic number.

It is an amenable number.

823638869 is a deficient number, since it is larger than the sum of its proper divisors (72727).

823638869 is a wasteful number, since it uses less digits than its factorization.

823638869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72726.

The product of its digits is 2985984, while the sum is 53.

The square root of 823638869 is about 28699.1092022035. The cubic root of 823638869 is about 937.3726500556.

The spelling of 823638869 in words is "eight hundred twenty-three million, six hundred thirty-eight thousand, eight hundred sixty-nine".