7764400640 has 40 divisors (see below), whose sum is σ = 18616369860. Its totient is φ = 3105759232.

The previous prime is 7764400627. The next prime is 7764400643. The reversal of 7764400640 is 460044677.

It can be written as a sum of positive squares in 2 ways, for example, as 7684976896 + 79423744 = 87664^2 + 8912^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 7764400594 and 7764400603.

It is not an unprimeable number, because it can be changed into a prime (7764400643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1513925 + ... + 1519044.

Almost surely, 2^7764400640 is an apocalyptic number.

It is an amenable number.

7764400640 is an abundant number, since it is smaller than the sum of its proper divisors (10851969220).

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

7764400640 is an equidigital number, since it uses as much as digits as its factorization.

7764400640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3032992 (or 3032976 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 38.

The square root of 7764400640 is about 88115.8364881138. The cubic root of 7764400640 is about 1980.1707705650.

The spelling of 7764400640 in words is "seven billion, seven hundred sixty-four million, four hundred thousand, six hundred forty".