856993 has 2 divisors, whose sum is σ = 856994. Its totient is φ = 856992.

The previous prime is 856969. The next prime is 857009. The reversal of 856993 is 399658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 762129 + 94864 = 873^2 + 308^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-856993 is a prime.

856993 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (856903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428496 + 428497.

It is an arithmetic number, because the mean of its divisors is an integer number (428497).

2⁸⁵⁶⁹⁹³ is an apocalyptic number.

It is an amenable number.

856993 is a deficient number, since it is larger than the sum of its proper divisors (1).

856993 is an equidigital number, since it uses as much as digits as its factorization.

856993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 40.

The square root of 856993 is about 925.7391641278. The cubic root of 856993 is about 94.9858889475.

It can be divided in two parts, 856 and 993, that added together give a square (1849 = 43²).

The spelling of 856993 in words is "eight hundred fifty-six thousand, nine hundred ninety-three".