855391 has 2 divisors, whose sum is σ = 855392. Its totient is φ = 855390.

The previous prime is 855377. The next prime is 855397. The reversal of 855391 is 193558.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 855391 - 2⁵ = 855359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (855397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427695 + 427696.

It is an arithmetic number, because the mean of its divisors is an integer number (427696).

2⁸⁵⁵³⁹¹ is an apocalyptic number.

855391 is a deficient number, since it is larger than the sum of its proper divisors (1).

855391 is an equidigital number, since it uses as much as digits as its factorization.

855391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5400, while the sum is 31.

The square root of 855391 is about 924.8735048643. The cubic root of 855391 is about 94.9266654729.

It can be divided in two parts, 85 and 5391, that added together give a square (5476 = 74²).

The spelling of 855391 in words is "eight hundred fifty-five thousand, three hundred ninety-one".