646859 has 2 divisors, whose sum is σ = 646860. Its totient is φ = 646858.

The previous prime is 646843. The next prime is 646873. The reversal of 646859 is 958646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646859 - 2⁴ = 646843 is a prime.

It is a super-3 number, since 3×646859³ = 811988969937653337, which contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (646879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323429 + 323430.

It is an arithmetic number, because the mean of its divisors is an integer number (323430).

2⁶⁴⁶⁸⁵⁹ is an apocalyptic number.

646859 is a deficient number, since it is larger than the sum of its proper divisors (1).

646859 is an equidigital number, since it uses as much as digits as its factorization.

646859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 38.

The square root of 646859 is about 804.2754503278. The cubic root of 646859 is about 86.4841540466.

It can be divided in two parts, 64 and 6859, that multiplied together give a cube (438976 = 76³).

The spelling of 646859 in words is "six hundred forty-six thousand, eight hundred fifty-nine".