856381 has 2 divisors, whose sum is σ = 856382. Its totient is φ = 856380.

The previous prime is 856369. The next prime is 856391. The reversal of 856381 is 183658.

856381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 793881 + 62500 = 891^2 + 250^2 .

It is a cyclic number.

It is not a de Polignac number, because 856381 - 2¹¹ = 854333 is a prime.

It is a super-2 number, since 2×856381² = 1466776834322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

856381 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428190 + 428191.

It is an arithmetic number, because the mean of its divisors is an integer number (428191).

2⁸⁵⁶³⁸¹ is an apocalyptic number.

It is an amenable number.

856381 is a deficient number, since it is larger than the sum of its proper divisors (1).

856381 is an equidigital number, since it uses as much as digits as its factorization.

856381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 31.

The square root of 856381 is about 925.4085584216. The cubic root of 856381 is about 94.9632729684.

The spelling of 856381 in words is "eight hundred fifty-six thousand, three hundred eighty-one".