644922433 has 2 divisors, whose sum is σ = 644922434. Its totient is φ = 644922432.

The previous prime is 644922413. The next prime is 644922463. The reversal of 644922433 is 334229446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 599858064 + 45064369 = 24492^2 + 6713^2 .

It is a cyclic number.

It is not a de Polignac number, because 644922433 - 2⁵ = 644922401 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644922392 and 644922401.

It is not a weakly prime, because it can be changed into another prime (644922413) 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 as a sum of consecutive naturals, namely, 322461216 + 322461217.

It is an arithmetic number, because the mean of its divisors is an integer number (322461217).

Almost surely, 2^644922433 is an apocalyptic number.

It is an amenable number.

644922433 is a deficient number, since it is larger than the sum of its proper divisors (1).

644922433 is an equidigital number, since it uses as much as digits as its factorization.

644922433 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 37.

The square root of 644922433 is about 25395.3230536648. The cubic root of 644922433 is about 863.9776233238.

It can be divided in two parts, 6449 and 22433, that added together give a palindrome (28882).

The spelling of 644922433 in words is "six hundred forty-four million, nine hundred twenty-two thousand, four hundred thirty-three".