664247 has 4 divisors (see below), whose sum is σ = 670800. Its totient is φ = 657696.

The previous prime is 664243. The next prime is 664253. The reversal of 664247 is 742466.

664247 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 742466 = 2 ⋅371233.

It is a cyclic number.

It is not a de Polignac number, because 664247 - 2² = 664243 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3122 + ... + 3327.

It is an arithmetic number, because the mean of its divisors is an integer number (167700).

2⁶⁶⁴²⁴⁷ is an apocalyptic number.

664247 is a deficient number, since it is larger than the sum of its proper divisors (6553).

664247 is a wasteful number, since it uses less digits than its factorization.

664247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6552.

The product of its digits is 8064, while the sum is 29.

The square root of 664247 is about 815.0134968208. The cubic root of 664247 is about 87.2522296729.

The spelling of 664247 in words is "six hundred sixty-four thousand, two hundred forty-seven".