2640687786 has 36 divisors (see below), whose sum is σ = 6288915906. Its totient is φ = 800207760.

The previous prime is 2640687781. The next prime is 2640687793. The reversal of 2640687786 is 6877860462.

It can be written as a sum of positive squares in only one way, i.e., 2640007161 + 680625 = 51381^2 + 825^2 .

It is not an unprimeable number, because it can be changed into a prime (2640687781) 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 17 ways as a sum of consecutive naturals, for example, 604041 + ... + 608396.

Almost surely, 2^2640687786 is an apocalyptic number.

2640687786 is an abundant number, since it is smaller than the sum of its proper divisors (3648228120).

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

2640687786 is a wasteful number, since it uses less digits than its factorization.

2640687786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212467 (or 1212453 counting only the distinct ones).

The product of its (nonzero) digits is 5419008, while the sum is 54.

The square root of 2640687786 is about 51387.6228872284. The cubic root of 2640687786 is about 1382.2046581149.

The spelling of 2640687786 in words is "two billion, six hundred forty million, six hundred eighty-seven thousand, seven hundred eighty-six".