820003685 has 4 divisors (see below), whose sum is σ = 984004428. Its totient is φ = 656002944.

The previous prime is 820003631. The next prime is 820003693. The reversal of 820003685 is 586300028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 410386564 + 409617121 = 20258^2 + 20239^2 .

It is a cyclic number.

It is not a de Polignac number, because 820003685 - 2¹⁰ = 820002661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82000364 + ... + 82000373.

It is an arithmetic number, because the mean of its divisors is an integer number (246001107).

Almost surely, 2^820003685 is an apocalyptic number.

It is an amenable number.

820003685 is a deficient number, since it is larger than the sum of its proper divisors (164000743).

820003685 is a wasteful number, since it uses less digits than its factorization.

820003685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164000742.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 820003685 is about 28635.7064693714. The cubic root of 820003685 is about 935.9915643948.

The spelling of 820003685 in words is "eight hundred twenty million, three thousand, six hundred eighty-five".