664129 has 4 divisors (see below), whose sum is σ = 687060. Its totient is φ = 641200.

The previous prime is 664123. The next prime is 664133. The reversal of 664129 is 921466.

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 540225 + 123904 = 735^2 + 352^2 .

It is a cyclic number.

It is not a de Polignac number, because 664129 - 2³ = 664121 is a prime.

It is a pancake number, because a pancake can be divided into 664129 parts by 1152 straight cuts.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 664097 and 664106.

It is not an unprimeable number, because it can be changed into a prime (664121) 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, 11422 + ... + 11479.

It is an arithmetic number, because the mean of its divisors is an integer number (171765).

2⁶⁶⁴¹²⁹ is an apocalyptic number.

It is an amenable number.

664129 is a deficient number, since it is larger than the sum of its proper divisors (22931).

664129 is a wasteful number, since it uses less digits than its factorization.

664129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22930.

The product of its digits is 2592, while the sum is 28.

The square root of 664129 is about 814.9411021663. The cubic root of 664129 is about 87.2470627331.

It can be divided in two parts, 6641 and 29, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 664129 in words is "six hundred sixty-four thousand, one hundred twenty-nine".