820987 has 4 divisors (see below), whose sum is σ = 826576. Its totient is φ = 815400.

The previous prime is 820969. The next prime is 820991. The reversal of 820987 is 789028.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-820987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820907) 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, 2568 + ... + 2869.

It is an arithmetic number, because the mean of its divisors is an integer number (206644).

2⁸²⁰⁹⁸⁷ is an apocalyptic number.

820987 is a deficient number, since it is larger than the sum of its proper divisors (5589).

820987 is a wasteful number, since it uses less digits than its factorization.

820987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5588.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 820987 is about 906.0833295012. The cubic root of 820987 is about 93.6365549258.

The spelling of 820987 in words is "eight hundred twenty thousand, nine hundred eighty-seven".