639241 has 4 divisors (see below), whose sum is σ = 645012. Its totient is φ = 633472.

The previous prime is 639211. The next prime is 639253. The reversal of 639241 is 142936.

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 32400 + 606841 = 180^2 + 779^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639241 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2716 + ... + 2941.

It is an arithmetic number, because the mean of its divisors is an integer number (161253).

2⁶³⁹²⁴¹ is an apocalyptic number.

It is an amenable number.

639241 is a deficient number, since it is larger than the sum of its proper divisors (5771).

639241 is a wasteful number, since it uses less digits than its factorization.

639241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5770.

The product of its digits is 1296, while the sum is 25.

The square root of 639241 is about 799.5254842718. The cubic root of 639241 is about 86.1433071267.

The spelling of 639241 in words is "six hundred thirty-nine thousand, two hundred forty-one".