664501 has 4 divisors (see below), whose sum is σ = 666252. Its totient is φ = 662752.

The previous prime is 664471. The next prime is 664507. The reversal of 664501 is 105466.

664501 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: 105466 = 2 ⋅52733.

It can be written as a sum of positive squares in 2 ways, for example, as 181476 + 483025 = 426^2 + 695^2 .

It is a cyclic number.

It is not a de Polignac number, because 664501 - 2¹⁵ = 631733 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 (664507) 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, 40 + ... + 1153.

It is an arithmetic number, because the mean of its divisors is an integer number (166563).

2⁶⁶⁴⁵⁰¹ is an apocalyptic number.

It is an amenable number.

664501 is a deficient number, since it is larger than the sum of its proper divisors (1751).

664501 is a wasteful number, since it uses less digits than its factorization.

664501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1750.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 664501 is about 815.1693075675. The cubic root of 664501 is about 87.2633496540.

Adding to 664501 its reverse (105466), we get a palindrome (769967).

The spelling of 664501 in words is "six hundred sixty-four thousand, five hundred one".