851215 has 4 divisors (see below), whose sum is σ = 1021464. Its totient is φ = 680968.

The previous prime is 851209. The next prime is 851231. The reversal of 851215 is 512158.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 512158 = 2 ⋅256079.

It is a cyclic number.

It is not a de Polignac number, because 851215 - 2⁷ = 851087 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable 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 3 ways as a sum of consecutive naturals, for example, 85117 + ... + 85126.

It is an arithmetic number, because the mean of its divisors is an integer number (255366).

2⁸⁵¹²¹⁵ is an apocalyptic number.

851215 is a deficient number, since it is larger than the sum of its proper divisors (170249).

851215 is a wasteful number, since it uses less digits than its factorization.

851215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170248.

The product of its digits is 400, while the sum is 22.

The square root of 851215 is about 922.6131366938. The cubic root of 851215 is about 94.7719367758.

The spelling of 851215 in words is "eight hundred fifty-one thousand, two hundred fifteen".