6778640 has 40 divisors (see below), whose sum is σ = 17195328. Its totient is φ = 2464640.

The previous prime is 6778637. The next prime is 6778643. The reversal of 6778640 is 468776.

It is an interprime number because it is at equal distance from previous prime (6778637) and next prime (6778643).

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 = 6778594 and 6778603.

It is not an unprimeable number, because it can be changed into a prime (6778643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2972 + ... + 4731.

Almost surely, 2^6778640 is an apocalyptic number.

It is an amenable number.

6778640 is an abundant number, since it is smaller than the sum of its proper divisors (10416688).

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

6778640 is a wasteful number, since it uses less digits than its factorization.

6778640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7727 (or 7721 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 38.

The square root of 6778640 is about 2603.5821477342. The cubic root of 6778640 is about 189.2550702566.

The spelling of 6778640 in words is "six million, seven hundred seventy-eight thousand, six hundred forty".