6636806440 has 72 divisors (see below), whose sum is σ = 16427783610. Its totient is φ = 2411323200.

The previous prime is 6636806431. The next prime is 6636806441. The reversal of 6636806440 is 446086366.

It can be written as a sum of positive squares in only one way, i.e., 5973125796 + 663680644 = 77286^2 + 25762^2 .

It is not an unprimeable number, because it can be changed into a prime (6636806441) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5667055 + ... + 5668225.

Almost surely, 2^6636806440 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 6636806440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8213891805).

6636806440 is an abundant number, since it is smaller than the sum of its proper divisors (9790977170).

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

6636806440 is a wasteful number, since it uses less digits than its factorization.

6636806440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2375 (or 1189 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 43.

The square root of 6636806440 is about 81466.5970812578. The cubic root of 6636806440 is about 1879.2578970845.

The spelling of 6636806440 in words is "six billion, six hundred thirty-six million, eight hundred six thousand, four hundred forty".