664771 has 2 divisors, whose sum is σ = 664772. Its totient is φ = 664770.

The previous prime is 664757. The next prime is 664777. The reversal of 664771 is 177466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664771 - 2⁵ = 664739 is a prime.

It is not a weakly prime, because it can be changed into another prime (664777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332385 + 332386.

It is an arithmetic number, because the mean of its divisors is an integer number (332386).

2⁶⁶⁴⁷⁷¹ is an apocalyptic number.

664771 is a deficient number, since it is larger than the sum of its proper divisors (1).

664771 is an equidigital number, since it uses as much as digits as its factorization.

664771 is an evil number, because the sum of its binary digits is even.

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

The square root of 664771 is about 815.3349005163. The cubic root of 664771 is about 87.2751669996.

The spelling of 664771 in words is "six hundred sixty-four thousand, seven hundred seventy-one".