6440005549 has 2 divisors, whose sum is σ = 6440005550. Its totient is φ = 6440005548.

The previous prime is 6440005547. The next prime is 6440005573. The reversal of 6440005549 is 9455000446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4451291524 + 1988714025 = 66718^2 + 44595^2 .

It is a cyclic number.

It is not a de Polignac number, because 6440005549 - 2¹ = 6440005547 is a prime.

Together with 6440005547, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6440005541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3220002774 + 3220002775.

It is an arithmetic number, because the mean of its divisors is an integer number (3220002775).

Almost surely, 2^6440005549 is an apocalyptic number.

It is an amenable number.

6440005549 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440005549 is an equidigital number, since it uses as much as digits as its factorization.

6440005549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 6440005549 is about 80249.6451643246. The cubic root of 6440005549 is about 1860.4960280527.

The spelling of 6440005549 in words is "six billion, four hundred forty million, five thousand, five hundred forty-nine".