646879 has 2 divisors, whose sum is σ = 646880. Its totient is φ = 646878.

The previous prime is 646873. The next prime is 646883. The reversal of 646879 is 978646.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323439 + 323440.

It is an arithmetic number, because the mean of its divisors is an integer number (323440).

2⁶⁴⁶⁸⁷⁹ is an apocalyptic number.

646879 is a deficient number, since it is larger than the sum of its proper divisors (1).

646879 is an equidigital number, since it uses as much as digits as its factorization.

646879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 646879 is about 804.2878837829. The cubic root of 646879 is about 86.4850453615.

The spelling of 646879 in words is "six hundred forty-six thousand, eight hundred seventy-nine".