6480642640 has 20 divisors (see below), whose sum is σ = 15067494324. Its totient is φ = 2592257024.

The previous prime is 6480642631. The next prime is 6480642677. The reversal of 6480642640 is 462460846.

It can be written as a sum of positive squares in 2 ways, for example, as 3147658816 + 3332983824 = 56104^2 + 57732^2 .

It is a tau number, because it is divible by the number of its divisors (20).

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 = 6480642593 and 6480642602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40503937 + ... + 40504096.

Almost surely, 2^6480642640 is an apocalyptic number.

It is an amenable number.

6480642640 is an abundant number, since it is smaller than the sum of its proper divisors (8586851684).

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

6480642640 is a wasteful number, since it uses less digits than its factorization.

6480642640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81008046 (or 81008040 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 40.

The square root of 6480642640 is about 80502.4387208239. The cubic root of 6480642640 is about 1864.4011321492.

The spelling of 6480642640 in words is "six billion, four hundred eighty million, six hundred forty-two thousand, six hundred forty".