664447 has 8 divisors (see below), whose sum is σ = 792576. Its totient is φ = 544632.

The previous prime is 664441. The next prime is 664459. The reversal of 664447 is 744466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 664447 - 2⁷ = 664319 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 (664441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1903 + ... + 2224.

It is an arithmetic number, because the mean of its divisors is an integer number (99072).

2⁶⁶⁴⁴⁴⁷ is an apocalyptic number.

664447 is a deficient number, since it is larger than the sum of its proper divisors (128129).

664447 is a wasteful number, since it uses less digits than its factorization.

664447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4157.

The product of its digits is 16128, while the sum is 31.

The square root of 664447 is about 815.1361849409. The cubic root of 664447 is about 87.2609858007.

It can be divided in two parts, 664 and 447, that added together give a palindrome (1111).

The spelling of 664447 in words is "six hundred sixty-four thousand, four hundred forty-seven".