851218 has 4 divisors (see below), whose sum is σ = 1276830. Its totient is φ = 425608.

The previous prime is 851209. The next prime is 851231. The reversal of 851218 is 812158.

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

It can be written as a sum of positive squares in only one way, i.e., 677329 + 173889 = 823^2 + 417^2 .

It is a junction number, because it is equal to n+sod(n) for n = 851192 and 851201.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 212803 + ... + 212806.

2⁸⁵¹²¹⁸ is an apocalyptic number.

851218 is a deficient number, since it is larger than the sum of its proper divisors (425612).

851218 is a wasteful number, since it uses less digits than its factorization.

851218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425611.

The product of its digits is 640, while the sum is 25.

The square root of 851218 is about 922.6147625093. The cubic root of 851218 is about 94.7720481129.

Subtracting from 851218 its reverse (812158), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 851218 in words is "eight hundred fifty-one thousand, two hundred eighteen".