644610513 has 8 divisors (see below), whose sum is σ = 871254688. Its totient is φ = 423853344.

The previous prime is 644610467. The next prime is 644610517. The reversal of 644610513 is 315016446.

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

It is not a de Polignac number, because 644610513 - 2⁸ = 644610257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644610517) 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, 1471495 + ... + 1471932.

It is an arithmetic number, because the mean of its divisors is an integer number (108906836).

Almost surely, 2^644610513 is an apocalyptic number.

It is an amenable number.

644610513 is a deficient number, since it is larger than the sum of its proper divisors (226644175).

644610513 is a wasteful number, since it uses less digits than its factorization.

644610513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2943503.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 644610513 is about 25389.1810226325. The cubic root of 644610513 is about 863.8383118112.

Adding to 644610513 its reverse (315016446), we get a palindrome (959626959).

The spelling of 644610513 in words is "six hundred forty-four million, six hundred ten thousand, five hundred thirteen".