851381 has 2 divisors, whose sum is σ = 851382. Its totient is φ = 851380.

The previous prime is 851363. The next prime is 851387. The reversal of 851381 is 183158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 722500 + 128881 = 850^2 + 359^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-851381 is a prime.

It is a super-2 number, since 2×851381² = 1449699214322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 851381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (851387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425690 + 425691.

It is an arithmetic number, because the mean of its divisors is an integer number (425691).

2⁸⁵¹³⁸¹ is an apocalyptic number.

It is an amenable number.

851381 is a deficient number, since it is larger than the sum of its proper divisors (1).

851381 is an equidigital number, since it uses as much as digits as its factorization.

851381 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 851381 is about 922.7030941749. The cubic root of 851381 is about 94.7780970365.

The spelling of 851381 in words is "eight hundred fifty-one thousand, three hundred eighty-one".