644267269 has 2 divisors, whose sum is σ = 644267270. Its totient is φ = 644267268.

The previous prime is 644267233. The next prime is 644267279. The reversal of 644267269 is 962762446.

644267269 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 572644900 + 71622369 = 23930^2 + 8463^2 .

It is a cyclic number.

It is not a de Polignac number, because 644267269 - 2¹¹ = 644265221 is a prime.

It is a super-2 number, since 2×644267269² = 830160627809436722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644267279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322133634 + 322133635.

It is an arithmetic number, because the mean of its divisors is an integer number (322133635).

Almost surely, 2^644267269 is an apocalyptic number.

It is an amenable number.

644267269 is a deficient number, since it is larger than the sum of its proper divisors (1).

644267269 is an equidigital number, since it uses as much as digits as its factorization.

644267269 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 46.

The square root of 644267269 is about 25382.4204716572. The cubic root of 644267269 is about 863.6849582458.

The spelling of 644267269 in words is "six hundred forty-four million, two hundred sixty-seven thousand, two hundred sixty-nine".