646771 has 2 divisors, whose sum is σ = 646772. Its totient is φ = 646770.

The previous prime is 646757. The next prime is 646781. The reversal of 646771 is 177646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646771 - 2⁷ = 646643 is a prime.

It is an Ulam number.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (646721) 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, 323385 + 323386.

It is an arithmetic number, because the mean of its divisors is an integer number (323386).

2⁶⁴⁶⁷⁷¹ is an apocalyptic number.

646771 is a deficient number, since it is larger than the sum of its proper divisors (1).

646771 is an equidigital number, since it uses as much as digits as its factorization.

646771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 31.

The square root of 646771 is about 804.2207408417. The cubic root of 646771 is about 86.4802320426.

The spelling of 646771 in words is "six hundred forty-six thousand, seven hundred seventy-one".