851731 has 2 divisors, whose sum is σ = 851732. Its totient is φ = 851730.

The previous prime is 851723. The next prime is 851749. The reversal of 851731 is 137158.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 851731 - 2³ = 851723 is a prime.

It is a super-2 number, since 2×851731² = 1450891392722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 851696 and 851705.

It is not a weakly prime, because it can be changed into another prime (851761) 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 as a sum of consecutive naturals, namely, 425865 + 425866.

It is an arithmetic number, because the mean of its divisors is an integer number (425866).

2⁸⁵¹⁷³¹ is an apocalyptic number.

851731 is a deficient number, since it is larger than the sum of its proper divisors (1).

851731 is an equidigital number, since it uses as much as digits as its factorization.

851731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 25.

The square root of 851731 is about 922.8927348289. The cubic root of 851731 is about 94.7910829145.

Adding to 851731 its reverse (137158), we get a palindrome (988889).

The spelling of 851731 in words is "eight hundred fifty-one thousand, seven hundred thirty-one".