6640255687 has 8 divisors (see below), whose sum is σ = 7461959904. Its totient is φ = 5862967968.

The previous prime is 6640255667. The next prime is 6640255691. The reversal of 6640255687 is 7865520466.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-6640255687 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 6640255687.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640255627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11103808 + ... + 11104405.

It is an arithmetic number, because the mean of its divisors is an integer number (932744988).

Almost surely, 2^6640255687 is an apocalyptic number.

6640255687 is a deficient number, since it is larger than the sum of its proper divisors (821704217).

6640255687 is a wasteful number, since it uses less digits than its factorization.

6640255687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22208249.

The product of its (nonzero) digits is 2419200, while the sum is 49.

The square root of 6640255687 is about 81487.7640323994. The cubic root of 6640255687 is about 1879.5834001263.

The spelling of 6640255687 in words is "six billion, six hundred forty million, two hundred fifty-five thousand, six hundred eighty-seven".