6543778 has 4 divisors (see below), whose sum is σ = 9815670. Its totient is φ = 3271888.

The previous prime is 6543773. The next prime is 6543781. The reversal of 6543778 is 8773456.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 3470769 + 3073009 = 1863^2 + 1753^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 6543778.

It is not an unprimeable number, because it can be changed into a prime (6543773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1635943 + ... + 1635946.

Almost surely, 2^6543778 is an apocalyptic number.

6543778 is a deficient number, since it is larger than the sum of its proper divisors (3271892).

6543778 is a wasteful number, since it uses less digits than its factorization.

6543778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3271891.

The product of its digits is 141120, while the sum is 40.

The square root of 6543778 is about 2558.0809213158. The cubic root of 6543778 is about 187.0435998883.

The spelling of 6543778 in words is "six million, five hundred forty-three thousand, seven hundred seventy-eight".