644730133 has 8 divisors (see below), whose sum is σ = 647682048. Its totient is φ = 641784624.

The previous prime is 644730131. The next prime is 644730137. The reversal of 644730133 is 331037446.

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

It is a cyclic number.

It is not a de Polignac number, because 644730133 - 2¹ = 644730131 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644730095 and 644730104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644730131) 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, 386860 + ... + 388522.

It is an arithmetic number, because the mean of its divisors is an integer number (80960256).

Almost surely, 2^644730133 is an apocalyptic number.

It is an amenable number.

644730133 is a deficient number, since it is larger than the sum of its proper divisors (2951915).

644730133 is a wasteful number, since it uses less digits than its factorization.

644730133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3203.

The product of its (nonzero) digits is 18144, while the sum is 31.

The square root of 644730133 is about 25391.5366411724. The cubic root of 644730133 is about 863.8917424982.

Adding to 644730133 its reverse (331037446), we get a palindrome (975767579).

The spelling of 644730133 in words is "six hundred forty-four million, seven hundred thirty thousand, one hundred thirty-three".