820087 has 4 divisors (see below), whose sum is σ = 823536. Its totient is φ = 816640.

The previous prime is 820073. The next prime is 820093. The reversal of 820087 is 780028.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1339 + ... + 1852.

It is an arithmetic number, because the mean of its divisors is an integer number (205884).

2⁸²⁰⁰⁸⁷ is an apocalyptic number.

820087 is a deficient number, since it is larger than the sum of its proper divisors (3449).

820087 is a wasteful number, since it uses less digits than its factorization.

820087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3448.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 820087 is about 905.5865502535. The cubic root of 820087 is about 93.6023263235.

It can be divided in two parts, 82008 and 7, that multiplied together give a triangular number (574056 = T₁₀₇₁).

The spelling of 820087 in words is "eight hundred twenty thousand, eighty-seven".