645936609 has 8 divisors (see below), whose sum is σ = 861369280. Its totient is φ = 430564176.

The previous prime is 645936569. The next prime is 645936617. The reversal of 645936609 is 906639546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645936609 - 2⁸ = 645936353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645936649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25812 + ... + 44250.

It is an arithmetic number, because the mean of its divisors is an integer number (107671160).

Almost surely, 2^645936609 is an apocalyptic number.

It is an amenable number.

645936609 is a deficient number, since it is larger than the sum of its proper divisors (215432671).

645936609 is a wasteful number, since it uses less digits than its factorization.

645936609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30119.

The product of its (nonzero) digits is 1049760, while the sum is 48.

The square root of 645936609 is about 25415.2829809152. The cubic root of 645936609 is about 864.4302702479.

The spelling of 645936609 in words is "six hundred forty-five million, nine hundred thirty-six thousand, six hundred nine".