644034869 has 2 divisors, whose sum is σ = 644034870. Its totient is φ = 644034868.

The previous prime is 644034841. The next prime is 644034899. The reversal of 644034869 is 968430446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 370562500 + 273472369 = 19250^2 + 16537^2 .

It is a cyclic number.

It is not a de Polignac number, because 644034869 - 2¹² = 644030773 is a prime.

It is a super-3 number, since 3×644034869³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644034829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322017434 + 322017435.

It is an arithmetic number, because the mean of its divisors is an integer number (322017435).

Almost surely, 2^644034869 is an apocalyptic number.

It is an amenable number.

644034869 is a deficient number, since it is larger than the sum of its proper divisors (1).

644034869 is an equidigital number, since it uses as much as digits as its factorization.

644034869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 497664, while the sum is 44.

The square root of 644034869 is about 25377.8420871437. The cubic root of 644034869 is about 863.5810963169.

The spelling of 644034869 in words is "six hundred forty-four million, thirty-four thousand, eight hundred sixty-nine".