820840873 has 4 divisors (see below), whose sum is σ = 820925380. Its totient is φ = 820756368.

The previous prime is 820840871. The next prime is 820840877. The reversal of 820840873 is 378048028.

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 139996224 + 680844649 = 11832^2 + 26093^2 .

It is a cyclic number.

It is not a de Polignac number, because 820840873 - 2¹ = 820840871 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820840871) 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, 25458 + ... + 47851.

It is an arithmetic number, because the mean of its divisors is an integer number (205231345).

Almost surely, 2^820840873 is an apocalyptic number.

It is an amenable number.

820840873 is a deficient number, since it is larger than the sum of its proper divisors (84507).

820840873 is a wasteful number, since it uses less digits than its factorization.

820840873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84506.

The product of its (nonzero) digits is 86016, while the sum is 40.

The square root of 820840873 is about 28650.3206439300. The cubic root of 820840873 is about 936.3099915748.

The spelling of 820840873 in words is "eight hundred twenty million, eight hundred forty thousand, eight hundred seventy-three".