642609 has 12 divisors (see below), whose sum is σ = 1012752. Its totient is φ = 389400.

The previous prime is 642581. The next prime is 642613. The reversal of 642609 is 906246.

642609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-642609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (642809) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3147 + ... + 3344.

It is an arithmetic number, because the mean of its divisors is an integer number (84396).

2⁶⁴²⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

642609 is a deficient number, since it is larger than the sum of its proper divisors (370143).

642609 is a wasteful number, since it uses less digits than its factorization.

642609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6508 (or 6505 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 642609 is about 801.6289665425. The cubic root of 642609 is about 86.2943313377.

The spelling of 642609 in words is "six hundred forty-two thousand, six hundred nine".