851813 has 2 divisors, whose sum is σ = 851814. Its totient is φ = 851812.

The previous prime is 851803. The next prime is 851821. The reversal of 851813 is 318158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 494209 + 357604 = 703^2 + 598^2 .

It is a cyclic number.

It is not a de Polignac number, because 851813 - 2⁴ = 851797 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (851803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425906 + 425907.

It is an arithmetic number, because the mean of its divisors is an integer number (425907).

2⁸⁵¹⁸¹³ is an apocalyptic number.

It is an amenable number.

851813 is a deficient number, since it is larger than the sum of its proper divisors (1).

851813 is an equidigital number, since it uses as much as digits as its factorization.

851813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 960, while the sum is 26.

The square root of 851813 is about 922.9371592909. The cubic root of 851813 is about 94.7941248058.

It can be divided in two parts, 85181 and 3, that added together give a cube (85184 = 44³).

The spelling of 851813 in words is "eight hundred fifty-one thousand, eight hundred thirteen".