664801 has 4 divisors (see below), whose sum is σ = 666900. Its totient is φ = 662704.

The previous prime is 664799. The next prime is 664843. The reversal of 664801 is 108466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 140625 + 524176 = 375^2 + 724^2 .

It is a cyclic number.

It is not a de Polignac number, because 664801 - 2¹ = 664799 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664891) 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, 466 + ... + 1243.

It is an arithmetic number, because the mean of its divisors is an integer number (166725).

2⁶⁶⁴⁸⁰¹ is an apocalyptic number.

It is an amenable number.

664801 is a deficient number, since it is larger than the sum of its proper divisors (2099).

664801 is a wasteful number, since it uses less digits than its factorization.

664801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2098.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 664801 is about 815.3532976569. The cubic root of 664801 is about 87.2764798405.

The spelling of 664801 in words is "six hundred sixty-four thousand, eight hundred one".