2640173778 has 90 divisors (see below), whose sum is σ = 6520416903. Its totient is φ = 797872680.

The previous prime is 2640173777. The next prime is 2640173791. The reversal of 2640173778 is 8773710462.

2640173778 is a `hidden beast` number, since 264 + 0 + 17 + 377 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1320086889 + 1320086889 = 36333^2 + 36333^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=36333.

It is not an unprimeable number, because it can be changed into a prime (2640173777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 7193751 + ... + 7194117.

Almost surely, 2^2640173778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2640173778

2640173778 is an abundant number, since it is smaller than the sum of its proper divisors (3880243125).

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

2640173778 is an equidigital number, since it uses as much as digits as its factorization.

2640173778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 770 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 395136, while the sum is 45.

The square root of 2640173778 is about 51382.6213617017. The cubic root of 2640173778 is about 1382.1149705775.

The spelling of 2640173778 in words is "two billion, six hundred forty million, one hundred seventy-three thousand, seven hundred seventy-eight".