6406464640 has 32 divisors (see below), whose sum is σ = 15315456060. Its totient is φ = 2562585600.

The previous prime is 6406464611. The next prime is 6406464653. The reversal of 6406464640 is 464646046.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5993237056 + 413227584 = 77416^2 + 20328^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 6406464593 and 6406464602.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5004411 + ... + 5005690.

Almost surely, 2^6406464640 is an apocalyptic number.

It is an amenable number.

6406464640 is an abundant number, since it is smaller than the sum of its proper divisors (8908991420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6406464640 is a wasteful number, since it uses less digits than its factorization.

6406464640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10010120 (or 10010108 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 40.

The square root of 6406464640 is about 80040.3938021297. The cubic root of 6406464640 is about 1857.2604522663.

The spelling of 6406464640 in words is "six billion, four hundred six million, four hundred sixty-four thousand, six hundred forty".