6400645544 has 16 divisors (see below), whose sum is σ = 12024165120. Its totient is φ = 3194201520.

The previous prime is 6400645507. The next prime is 6400645579. The reversal of 6400645544 is 4455460046.

It is a junction number, because it is equal to n+sod(n) for n = 6400645498 and 6400645507.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 760712 + ... + 769079.

It is an arithmetic number, because the mean of its divisors is an integer number (751510320).

Almost surely, 2^6400645544 is an apocalyptic number.

It is an amenable number.

6400645544 is a deficient number, since it is larger than the sum of its proper divisors (5623519576).

6400645544 is a wasteful number, since it uses less digits than its factorization.

6400645544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1530320 (or 1530316 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 38.

The square root of 6400645544 is about 80004.0345482651. The cubic root of 6400645544 is about 1856.6979553010.

The spelling of 6400645544 in words is "six billion, four hundred million, six hundred forty-five thousand, five hundred forty-four".