644624533 has 8 divisors (see below), whose sum is σ = 775488320. Its totient is φ = 523454400.

The previous prime is 644624489. The next prime is 644624537. The reversal of 644624533 is 335426446.

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 644624533 - 2⁹ = 644624021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644624492 and 644624501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644624537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2423268 + ... + 2423533.

It is an arithmetic number, because the mean of its divisors is an integer number (96936040).

Almost surely, 2^644624533 is an apocalyptic number.

It is an amenable number.

644624533 is a deficient number, since it is larger than the sum of its proper divisors (130863787).

644624533 is a wasteful number, since it uses less digits than its factorization.

644624533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4846827.

The product of its digits is 207360, while the sum is 37.

The square root of 644624533 is about 25389.4571229871. The cubic root of 644624533 is about 863.8445744691.

The spelling of 644624533 in words is "six hundred forty-four million, six hundred twenty-four thousand, five hundred thirty-three".