6534665640 has 48 divisors (see below), whose sum is σ = 21237664500. Its totient is φ = 1742577408.

The previous prime is 6534665597. The next prime is 6534665647. The reversal of 6534665640 is 465664356.

6534665640 is a `hidden beast` number, since 6 + 534 + 66 + 56 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6292614276 + 242051364 = 79326^2 + 15558^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (6534665647) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 9075565 + ... + 9076284.

Almost surely, 2^6534665640 is an apocalyptic number.

6534665640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6534665640 is an abundant number, since it is smaller than the sum of its proper divisors (14702998860).

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

6534665640 is a wasteful number, since it uses less digits than its factorization.

6534665640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18151866 (or 18151859 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 45.

The square root of 6534665640 is about 80837.2787765645. The cubic root of 6534665640 is about 1869.5673873191.

The spelling of 6534665640 in words is "six billion, five hundred thirty-four million, six hundred sixty-five thousand, six hundred forty".