851688 has 32 divisors (see below), whose sum is σ = 2366400. Its totient is φ = 283824.

The previous prime is 851677. The next prime is 851689. The reversal of 851688 is 886158.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (851689) by changing a digit.

851688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1756 + ... + 2187.

It is an arithmetic number, because the mean of its divisors is an integer number (73950).

2⁸⁵¹⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

851688 is an abundant number, since it is smaller than the sum of its proper divisors (1514712).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

851688 is a wasteful number, since it uses less digits than its factorization.

851688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3958 (or 3948 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 851688 is about 922.8694382197. The cubic root of 851688 is about 94.7894876983.

The spelling of 851688 in words is "eight hundred fifty-one thousand, six hundred eighty-eight".