6406644557 has 2 divisors, whose sum is σ = 6406644558. Its totient is φ = 6406644556.

The previous prime is 6406644539. The next prime is 6406644583. The reversal of 6406644557 is 7554466046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3459674761 + 2946969796 = 58819^2 + 54286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6406644557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6406644527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3203322278 + 3203322279.

It is an arithmetic number, because the mean of its divisors is an integer number (3203322279).

Almost surely, 2^6406644557 is an apocalyptic number.

It is an amenable number.

6406644557 is a deficient number, since it is larger than the sum of its proper divisors (1).

6406644557 is an equidigital number, since it uses as much as digits as its factorization.

6406644557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2419200, while the sum is 47.

The square root of 6406644557 is about 80041.5177079995. The cubic root of 6406644557 is about 1857.2778383296.

The spelling of 6406644557 in words is "six billion, four hundred six million, six hundred forty-four thousand, five hundred fifty-seven".