851261 has 2 divisors, whose sum is σ = 851262. Its totient is φ = 851260.

The previous prime is 851251. The next prime is 851267. The reversal of 851261 is 162158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 755161 + 96100 = 869^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 851261 - 2⁶ = 851197 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 (851267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425630 + 425631.

It is an arithmetic number, because the mean of its divisors is an integer number (425631).

2⁸⁵¹²⁶¹ is an apocalyptic number.

It is an amenable number.

851261 is a deficient number, since it is larger than the sum of its proper divisors (1).

851261 is an equidigital number, since it uses as much as digits as its factorization.

851261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 23.

The square root of 851261 is about 922.6380655490. The cubic root of 851261 is about 94.7736439162.

It can be divided in two parts, 851 and 261, that multiplied together give a triangular number (222111 = T₆₆₆).

The spelling of 851261 in words is "eight hundred fifty-one thousand, two hundred sixty-one".