644269433 has 2 divisors, whose sum is σ = 644269434. Its totient is φ = 644269432.

The previous prime is 644269393. The next prime is 644269447. The reversal of 644269433 is 334962446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 527023849 + 117245584 = 22957^2 + 10828^2 .

It is a cyclic number.

It is not a de Polignac number, because 644269433 - 2¹⁰ = 644268409 is a prime.

It is not a weakly prime, because it can be changed into another prime (644269453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322134716 + 322134717.

It is an arithmetic number, because the mean of its divisors is an integer number (322134717).

Almost surely, 2^644269433 is an apocalyptic number.

It is an amenable number.

644269433 is a deficient number, since it is larger than the sum of its proper divisors (1).

644269433 is an equidigital number, since it uses as much as digits as its factorization.

644269433 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 41.

The square root of 644269433 is about 25382.4630995497. The cubic root of 644269433 is about 863.6859252420.

The spelling of 644269433 in words is "six hundred forty-four million, two hundred sixty-nine thousand, four hundred thirty-three".