644265433 has 8 divisors (see below), whose sum is σ = 775056320. Its totient is φ = 523162800.

The previous prime is 644265409. The next prime is 644265437. The reversal of 644265433 is 334562446.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644265433 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644265392 and 644265401.

It is not an unprimeable number, because it can be changed into a prime (644265437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2421918 + ... + 2422183.

It is an arithmetic number, because the mean of its divisors is an integer number (96882040).

Almost surely, 2^644265433 is an apocalyptic number.

It is an amenable number.

644265433 is a deficient number, since it is larger than the sum of its proper divisors (130790887).

644265433 is a wasteful number, since it uses less digits than its factorization.

644265433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4844127.

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

The square root of 644265433 is about 25382.3843048678. The cubic root of 644265433 is about 863.6841378165.

The spelling of 644265433 in words is "six hundred forty-four million, two hundred sixty-five thousand, four hundred thirty-three".