6440507641 has 6 divisors (see below), whose sum is σ = 6654968826. Its totient is φ = 6232748400.

The previous prime is 6440507617. The next prime is 6440507669. The reversal of 6440507641 is 1467050446.

It can be written as a sum of positive squares in only one way, i.e., 3271268025 + 3169239616 = 57195^2 + 56296^2 .

It is not a de Polignac number, because 6440507641 - 2⁵ = 6440507609 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6440507641.

It is not an unprimeable number, because it can be changed into a prime (6440507611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3349980 + ... + 3351901.

It is an arithmetic number, because the mean of its divisors is an integer number (1109161471).

Almost surely, 2^6440507641 is an apocalyptic number.

It is an amenable number.

6440507641 is a deficient number, since it is larger than the sum of its proper divisors (214461185).

6440507641 is an equidigital number, since it uses as much as digits as its factorization.

6440507641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6701943 (or 6701912 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 37.

The square root of 6440507641 is about 80252.7734162502. The cubic root of 6440507641 is about 1860.5443776951.

The spelling of 6440507641 in words is "six billion, four hundred forty million, five hundred seven thousand, six hundred forty-one".