856987 has 4 divisors (see below), whose sum is σ = 907416. Its totient is φ = 806560.

The previous prime is 856969. The next prime is 856993. The reversal of 856987 is 789658.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789658 = 2 ⋅394829.

It is a cyclic number.

It is not a de Polignac number, because 856987 - 2¹⁹ = 332699 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856927) 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, 25189 + ... + 25222.

It is an arithmetic number, because the mean of its divisors is an integer number (226854).

2⁸⁵⁶⁹⁸⁷ is an apocalyptic number.

856987 is a deficient number, since it is larger than the sum of its proper divisors (50429).

856987 is a wasteful number, since it uses less digits than its factorization.

856987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50428.

The product of its digits is 120960, while the sum is 43.

The square root of 856987 is about 925.7359234685. The cubic root of 856987 is about 94.9856672745.

The spelling of 856987 in words is "eight hundred fifty-six thousand, nine hundred eighty-seven".