851866 has 8 divisors (see below), whose sum is σ = 1287540. Its totient is φ = 422688.

The previous prime is 851863. The next prime is 851881. The reversal of 851866 is 668158.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 837225 + 14641 = 915^2 + 121^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (851863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1281 + ... + 1828.

2⁸⁵¹⁸⁶⁶ is an apocalyptic number.

851866 is a deficient number, since it is larger than the sum of its proper divisors (435674).

851866 is a wasteful number, since it uses less digits than its factorization.

851866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3248.

The product of its digits is 11520, while the sum is 34.

The square root of 851866 is about 922.9658715251. The cubic root of 851866 is about 94.7960908024.

The spelling of 851866 in words is "eight hundred fifty-one thousand, eight hundred sixty-six".