644461133 has 16 divisors (see below), whose sum is σ = 694552320. Its totient is φ = 596054016.

The previous prime is 644461091. The next prime is 644461151. The reversal of 644461133 is 331164446.

644461133 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644461133 - 2²⁸ = 376025677 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644461133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644461163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 528941 + ... + 530157.

It is an arithmetic number, because the mean of its divisors is an integer number (43409520).

Almost surely, 2^644461133 is an apocalyptic number.

It is an amenable number.

644461133 is a deficient number, since it is larger than the sum of its proper divisors (50091187).

644461133 is a wasteful number, since it uses less digits than its factorization.

644461133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1876.

The product of its digits is 20736, while the sum is 32.

The square root of 644461133 is about 25386.2390479567. The cubic root of 644461133 is about 863.7715789374.

The spelling of 644461133 in words is "six hundred forty-four million, four hundred sixty-one thousand, one hundred thirty-three".