820608869 has 4 divisors (see below), whose sum is σ = 820686444. Its totient is φ = 820531296.

The previous prime is 820608847. The next prime is 820608871. The reversal of 820608869 is 968806028.

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 397483969 + 423124900 = 19937^2 + 20570^2 .

It is a cyclic number.

It is not a de Polignac number, because 820608869 - 2²⁴ = 803831653 is a prime.

It is a super-2 number, since 2×820608869² = 1346797831762918322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820608839) 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, 19832 + ... + 45105.

It is an arithmetic number, because the mean of its divisors is an integer number (205171611).

Almost surely, 2^820608869 is an apocalyptic number.

It is an amenable number.

820608869 is a deficient number, since it is larger than the sum of its proper divisors (77575).

820608869 is a wasteful number, since it uses less digits than its factorization.

820608869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77574.

The product of its (nonzero) digits is 331776, while the sum is 47.

The square root of 820608869 is about 28646.2714676797. The cubic root of 820608869 is about 936.2217697933.

The spelling of 820608869 in words is "eight hundred twenty million, six hundred eight thousand, eight hundred sixty-nine".