644450269 has 2 divisors, whose sum is σ = 644450270. Its totient is φ = 644450268.

The previous prime is 644450251. The next prime is 644450293. The reversal of 644450269 is 962054446.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 419840100 + 224610169 = 20490^2 + 14987^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644450269 is a prime.

It is a super-2 number, since 2×644450269² = 830632298428344722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644450239) 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 as a sum of consecutive naturals, namely, 322225134 + 322225135.

It is an arithmetic number, because the mean of its divisors is an integer number (322225135).

Almost surely, 2^644450269 is an apocalyptic number.

It is an amenable number.

644450269 is a deficient number, since it is larger than the sum of its proper divisors (1).

644450269 is an equidigital number, since it uses as much as digits as its factorization.

644450269 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 644450269 is about 25386.0250728624. The cubic root of 644450269 is about 863.7667252352.

The spelling of 644450269 in words is "six hundred forty-four million, four hundred fifty thousand, two hundred sixty-nine".