6640855956 has 120 divisors (see below), whose sum is σ = 20023351040. Its totient is φ = 1879910208.

The previous prime is 6640855943. The next prime is 6640855999. The reversal of 6640855956 is 6595580466.

6640855956 is a `hidden beast` number, since 6 + 6 + 40 + 8 + 5 + 595 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 233781 + ... + 260643.

Almost surely, 2^6640855956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6640855956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10011675520).

6640855956 is an abundant number, since it is smaller than the sum of its proper divisors (13382495084).

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

6640855956 is a wasteful number, since it uses less digits than its factorization.

6640855956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26995 (or 26984 counting only the distinct ones).

The product of its (nonzero) digits is 7776000, while the sum is 54.

The square root of 6640855956 is about 81491.4471340398. The cubic root of 6640855956 is about 1879.6400355786.

The spelling of 6640855956 in words is "six billion, six hundred forty million, eight hundred fifty-five thousand, nine hundred fifty-six".