642641 has 4 divisors (see below), whose sum is σ = 645300. Its totient is φ = 639984.

The previous prime is 642623. The next prime is 642673. The reversal of 642641 is 146246.

It is a happy number.

642641 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.

It can be written as a sum of positive squares in 2 ways, for example, as 87616 + 555025 = 296^2 + 745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642641 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (642241) 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, 926 + ... + 1463.

It is an arithmetic number, because the mean of its divisors is an integer number (161325).

2⁶⁴²⁶⁴¹ is an apocalyptic number.

It is an amenable number.

642641 is a deficient number, since it is larger than the sum of its proper divisors (2659).

642641 is a wasteful number, since it uses less digits than its factorization.

642641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2658.

The product of its digits is 1152, while the sum is 23.

The square root of 642641 is about 801.6489256526. The cubic root of 642641 is about 86.2957637135.

Adding to 642641 its reverse (146246), we get a palindrome (788887).

The spelling of 642641 in words is "six hundred forty-two thousand, six hundred forty-one".