851651 has 4 divisors (see below), whose sum is σ = 855600. Its totient is φ = 847704.

The previous prime is 851647. The next prime is 851659. The reversal of 851651 is 156158.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 156158 = 2 ⋅78079.

It is a cyclic number.

It is not a de Polignac number, because 851651 - 2² = 851647 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 851651.

It is not an unprimeable number, because it can be changed into a prime (851659) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1631 + ... + 2088.

It is an arithmetic number, because the mean of its divisors is an integer number (213900).

2⁸⁵¹⁶⁵¹ is an apocalyptic number.

851651 is a deficient number, since it is larger than the sum of its proper divisors (3949).

851651 is a wasteful number, since it uses less digits than its factorization.

851651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3948.

The product of its digits is 1200, while the sum is 26.

The square root of 851651 is about 922.8493918295. The cubic root of 851651 is about 94.7881150275.

The spelling of 851651 in words is "eight hundred fifty-one thousand, six hundred fifty-one".